programming

Làm thế nào để bạn khớp hai từ trong regex?

Biểu thức chính quy, hoặc ngắn gọn là regex hoặc regexp, cực kỳ mạnh mẽ và đáng kinh ngạc trong việc tìm kiếm và thao tác với các chuỗi văn bản, đặc biệt là trong việc xử lý các tệp văn bản. Một dòng regex có thể dễ dàng thay thế vài chục dòng mã lập trình

Regex được hỗ trợ trong tất cả các ngôn ngữ kịch bản [chẳng hạn như Perl, Python, PHP và JavaScript]; . Bắt đầu với regex có thể không dễ dàng do cú pháp phức tạp của nó, nhưng nó chắc chắn đáng để bạn đầu tư thời gian

Regex theo ví dụ

Phần này dành cho những người cần làm mới bộ nhớ của họ. Đối với những người mới làm quen, hãy chuyển sang phần tiếp theo để tìm hiểu cú pháp, trước khi xem các ví dụ này

Tóm tắt cú pháp Regex

Nhân vật. Tất cả các ký tự, ngoại trừ những ký tự có ý nghĩa đặc biệt trong biểu thức chính quy, khớp với chính chúng. e. g. , regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

11 khớp với chuỗi con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

12;

Ký tự Regex đặc biệt. Những ký tự này có ý nghĩa đặc biệt trong regex [sẽ được thảo luận bên dưới].

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

01,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

02,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

03,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

05,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Chuỗi thoát [\char]

Để khớp một ký tự có ý nghĩa đặc biệt trong biểu thức chính quy, bạn cần sử dụng tiền tố chuỗi thoát với dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08]. e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 trận đấu ________ 201;

Bạn cũng cần sử dụng regex ________ 206 để khớp với ________ 207 [dấu gạch chéo ngược]

Regex nhận ra các chuỗi thoát phổ biến như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 cho dòng mới,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

09 cho tab,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 cho ký tự xuống dòng,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

01 cho số bát phân có 3 chữ số,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

02 cho mã hex gồm hai chữ số,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

03 cho Unicode 4 chữ số,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Một dãy ký tự [hoặc chuỗi]. Các chuỗi có thể được khớp thông qua việc kết hợp một chuỗi ký tự [được gọi là biểu thức con]. e. g. , regex ________ 305 phù hợp với ________ 306. Theo mặc định, đối sánh phân biệt chữ hoa chữ thường nhưng có thể được đặt thành không phân biệt chữ hoa chữ thường thông qua công cụ sửa đổi

Toán tử HOẶC [. ]. e. g. , regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07 chấp nhận chuỗi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Lớp ký tự [hoặc Danh sách khung]

[. ]. Chấp nhận BẤT KỲ MỘT ký tự nào trong dấu ngoặc vuông, e. g. , ________ 400 trận đấu ________ 401, ________ 402, _______ 403,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

[. -. ] [Biểu thức phạm vi]. Chấp nhận BẤT KỲ MỘT ký tự nào trong phạm vi, e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 khớp với bất kỳ chữ số nào;

[^. ]. KHÔNG CÓ MỘT nhân vật nào, e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 khớp với bất kỳ chữ số nào

Chỉ bốn ký tự này yêu cầu chuỗi thoát bên trong danh sách dấu ngoặc. ________ 09, ________ 500, ________ 104, ________ 108

Chỉ báo xuất hiện [hoặc Toán tử lặp lại]

+. một hoặc nhiều [______503], e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04 khớp với một hoặc nhiều chữ số, chẳng hạn như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

05,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

*. không hoặc nhiều hơn [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07], e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 khớp với 0 hoặc nhiều chữ số. Nó chấp nhận tất cả những thứ trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04 cộng với chuỗi rỗng

?. không hoặc một [tùy chọn], e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

110 khớp với một tùy chọn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

03,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

112 hoặc một chuỗi rỗng

{m,n}.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

113 đến

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

114 [bao gồm cả hai]

{m}. chính xác

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

113 lần

{m,}.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

113 trở lên [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

117]

Siêu ký tự. khớp với một ký tự

[chấm]. BẤT KỲ MỘT ký tự nào ngoại trừ dòng mới. Tương tự như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

118

\d, \D. MỘT chữ số/ký tự không phải chữ số BẤT KỲ. Các chữ số là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

\w, \W. BẤT KỲ MỘT từ/ký tự không phải từ nào. Đối với ASCII, các ký tự từ là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

120

\s, \S. BẤT KỲ MỘT ký tự khoảng trắng/ký tự không khoảng trắng nào. Đối với ASCII, các ký tự khoảng trắng là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

121

Vị trí neo. không khớp với ký tự, nhưng vị trí như đầu dòng, cuối dòng, đầu từ và cuối từ

^, $. đầu dòng và cuối dòng tương ứng. e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

122 khớp với một chuỗi số

\ b. ranh giới của từ, tôi. e. , đầu từ hoặc cuối từ. e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

123 khớp với từ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

124 trong chuỗi đầu vào

\B. Nghịch đảo của \b, i. e. , không bắt đầu từ hoặc không kết thúc từ

\: start-of-word and end-of-word respectively, similar to

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

125. E.g.,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 matches the word

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

124 in the input string.

\A,\Z. bắt đầu đầu vào và kết thúc đầu vào tương ứng

Tài liệu tham khảo quay lại ngoặc đơn

Sử dụng dấu ngoặc đơn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

128 để tạo tham chiếu ngược

Sử dụng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

130,. [Java, Perl, JavaScript] hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

131,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

132,. [Python] để truy xuất các tham chiếu ngược theo thứ tự tuần tự

Lười biếng [Kiềm chế sự tham lam cho các toán tử lặp lại].

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

133,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

134,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

135,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

136,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

137

Ví dụ. Số [0-9]+ hoặc \d+

Một biểu thức chính quy [biểu thức chính quy] bao gồm một chuỗi các biểu thức con. Trong ví dụ này,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00, được gọi là lớp ký tự [hoặc danh sách ngoặc], bao gồm một danh sách các ký tự. Nó khớp với bất kỳ ký tự SINGLE nào trong danh sách. Trong ví dụ này,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 khớp với bất kỳ ký tự DUY NHẤT nào trong khoảng từ 0 đến 9 [i. e. , một chữ số], trong đó dấu gạch ngang [_______500] biểu thị phạm vi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6, được gọi là chỉ số xuất hiện [hoặc toán tử lặp lại], cho biết một hoặc nhiều lần xuất hiện [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

03] của biểu thức con trước đó. Trong trường hợp này,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04 khớp với một hoặc nhiều chữ số

Một biểu thức chính quy có thể khớp với một phần của đầu vào [i. e. , chuỗi con] hoặc toàn bộ đầu vào. Trên thực tế, nó có thể khớp với 0 hoặc nhiều chuỗi con của đầu vào [với công cụ sửa đổi toàn cầu]

Regex này khớp với bất kỳ chuỗi con số nào [có chữ số từ 0 đến 9] của đầu vào. Ví dụ như,

Nếu đầu vào là ________ 006, nó khớp với chuỗi con ________ 007

Nếu đầu vào là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08, nó không khớp với gì

Nếu đầu vào là ________ 009, thì nó sẽ khớp với các chuỗi con ________ 010, ________ 011 và ________ 012 [ba trận đấu]

Hãy lưu ý rằng biểu thức chính quy này khớp với số có số 0 đứng đầu, chẳng hạn như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

13,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

14 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

15, điều này có thể không được mong muốn

Bạn cũng có thể viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

16, trong đó

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17 được biết đến như một siêu ký tự khớp với bất kỳ chữ số nào [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06]. Có nhiều hơn một cách để viết regex. Hãy lưu ý rằng nhiều ngôn ngữ lập trình [C, Java, JavaScript, Python] sử dụng dấu gạch chéo ngược

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 làm tiền tố cho các chuỗi thoát [e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 cho dòng mới] và thay vào đó bạn cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Ví dụ về mã [Python, Java, JavaScript, Perl, PHP]

Mã Ví dụ trong Python

Xem "" để được bảo hiểm đầy đủ

Python hỗ trợ Regex thông qua mô-đun

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

22. Python cũng sử dụng dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08] cho các chuỗi thoát [i. e. , bạn cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

27 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17], nhưng nó hỗ trợ chuỗi thô ở dạng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

29, loại bỏ qua việc giải thích các chuỗi thoát - rất phù hợp để viết biểu thức chính quy

Mã Ví dụ trong Java

Xem "Biểu thức chính quy [Regex] trong Java" để biết đầy đủ

Java hỗ trợ Regex trong gói

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

đầu ra là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Mã Ví dụ trong Perl

Xem "" để được bảo hiểm đầy đủ

Perl sử dụng rộng rãi các biểu thức chính quy với nhiều cú pháp và toán tử tích hợp sẵn. Trong Perl [và JavaScript], một biểu thức chính quy được phân tách bằng một cặp dấu gạch chéo lên [mặc định], ở dạng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

31. Bạn có thể sử dụng các toán tử tích hợp

m/regex/công cụ sửa đổi hoặc /regex/công cụ sửa đổi. Trận đấu với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

32.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

113 là tùy chọn

s/regex/thay thế/sửa đổi. Thay thế [các] chuỗi con phù hợp bằng chuỗi thay thế

Trong Perl, bạn có thể sử dụng chuỗi không nội suy được trích dẫn một lần

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

34 để viết biểu thức chính quy nhằm vô hiệu hóa việc giải thích dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08] của Perl

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

0Ví dụ mã trong JavaScript

Xem "" để được bảo hiểm đầy đủ

Trong JavaScript [và Perl], một biểu thức chính quy được phân định bằng một cặp dấu gạch chéo về phía trước, ở dạng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

36. Có hai bộ phương thức, phát hành thông qua đối tượng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

37 hoặc đối tượng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

0Mã ví dụ trong PHP

[LÀM]

Ví dụ. Chuỗi số đầy đủ ^[0-9]+$ hoặc ^\d+$

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 dẫn đầu và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 theo sau được gọi là neo vị trí, tương ứng khớp với vị trí bắt đầu và kết thúc của dòng. Kết quả là, toàn bộ chuỗi đầu vào sẽ được khớp hoàn toàn, thay vì một phần của chuỗi đầu vào [chuỗi con]

Regex này khớp với bất kỳ chuỗi số không trống nào [bao gồm các chữ số từ 0 đến 9], e. g. , "______041" và "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

42". Nó không khớp với "" [chuỗi trống], "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

43", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

44", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

45", v.v. Tuy nhiên, nó cũng khớp với "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

46", "______047" và "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

48" với các số 0 ở đầu

Ví dụ. Số nguyên dương [1-9][0-9]. 0 hoặc [1-9]\d. 0

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

49 khớp với bất kỳ ký tự nào từ 1 đến 9; .

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

7 là chỉ số xuất hiện đại diện cho 0 hoặc nhiều lần xuất hiện. Cùng với nhau,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

52 khớp với bất kỳ số nào không có số 0 đứng đầu

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07 đại diện cho toán tử OR;

Biểu thức này khớp với "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

41" và "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

56";

Bạn có thể thay thế

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 bằng siêu ký tự

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17, nhưng không thể thay thế

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Chúng tôi đã không sử dụng neo vị trí

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 trong biểu thức chính quy này. Do đó, nó có thể khớp với bất kỳ phần nào của chuỗi đầu vào. Ví dụ như,

Nếu chuỗi đầu vào là "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

45", nó khớp với chuỗi con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Nếu chuỗi đầu vào là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08, nó không khớp với gì

Nếu chuỗi đầu vào là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

67, nó sẽ khớp với các chuỗi con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

11 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

12 [ba khớp]

Nếu chuỗi đầu vào là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

71, nó khớp với các chuỗi con.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

12,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

12 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

74 [ba trận]

Ví dụ. Chữ số nguyên đầy đủ ^[+-]?[1-9][0-9]. 0$ hoặc ^[+-]?[1-9]\d. 0$

Regex này khớp với một chữ số nguyên [cho toàn bộ chuỗi có neo vị trí], cả dương, âm và 0

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

75 phù hợp với dấu hiệu của

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8 là chỉ số xuất hiện biểu thị 0 hoặc 1 lần xuất hiện, i. e. không bắt buộc. Do đó,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

110 phù hợp với dấu hiệu tùy chọn hàng đầu của

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Chúng tôi đã đề cập đến ba chỉ số xuất hiện.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6 cho một hoặc nhiều,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

7 cho số không hoặc nhiều hơn và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8 cho số không hoặc một

Ví dụ. Mã định danh [hoặc Tên] [a-zA-Z_][0-9a-zA-Z_]* hoặc [a-zA-Z_]\w*

Bắt đầu bằng một chữ cái hoặc dấu gạch dưới, theo sau là số không hoặc nhiều chữ số, chữ cái và dấu gạch dưới

Bạn có thể sử dụng siêu ký tự

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85 cho ký tự từ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

120. Nhớ lại rằng siêu ký tự

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17 có thể được sử dụng cho một chữ số

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Ví dụ. Tên tệp hình ảnh ^\w+\. [gif. png. jpg. jpeg]$

Các neo vị trí

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 lần lượt khớp với phần đầu và phần cuối của chuỗi đầu vào. Nghĩa là, biểu thức chính quy này sẽ khớp với toàn bộ chuỗi đầu vào, thay vì một phần của chuỗi đầu vào [chuỗi con]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

91 khớp với một hoặc nhiều ký tự từ [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

92]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 khớp với dấu chấm

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

94 ký tự. Chúng ta cần sử dụng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 để đại diện cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 vì

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 có ý nghĩa đặc biệt trong biểu thức chính quy.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 được gọi là mã thoát, giúp khôi phục nghĩa đen ban đầu của ký tự sau. Tương tự,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8 [các chỉ số xuất hiện],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 [các neo vị trí] có ý nghĩa đặc biệt trong biểu thức chính quy. Bạn cần sử dụng mã thoát để khớp với các ký tự này

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

004 khớp với "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

005", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

006", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

007" hoặc "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

008".

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07 biểu thị toán tử "HOẶC". Các dấu ngoặc đơn được sử dụng để nhóm các lựa chọn

Công cụ sửa đổi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

010 sau biểu thức chính quy chỉ định khớp không phân biệt chữ hoa chữ thường [chỉ áp dụng cho một số ngôn ngữ như Perl và JavaScript]. Nghĩa là, nó chấp nhận "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

011" và "______1012"

Ví dụ. Địa chỉ email ^\w+[[. -]?\w+]@\w+[[. -]?\w+][\. \w{2,3}]+$

Các neo vị trí

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

91 khớp với 1 hoặc nhiều ký tự từ [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

92]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

017 khớp với ký tự tùy chọn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00. Mặc dù dấu chấm [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5] có ý nghĩa đặc biệt trong biểu thức chính quy, nhưng trong một lớp ký tự [dấu ngoặc vuông], bất kỳ ký tự nào ngoại trừ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 đều là ký tự bằng chữ và không yêu cầu chuỗi ký tự thoát

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

025 khớp với 0 lần xuất hiện trở lên của

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

026

Biểu thức con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

027 dùng để ghép tên người dùng trong email, trước dấu

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

3. Nó bắt đầu bằng ít nhất một ký tự từ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

120, tiếp theo là nhiều ký tự từ hơn hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00. Tuy nhiên, một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 phải theo sau một ký tự từ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

120. Nghĩa là, chuỗi đầu vào không thể bắt đầu bằng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00; . Ví dụ về chuỗi hợp lệ là "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

041"

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

3 khớp với chính nó. Trong regex, tất cả các ký tự khác với những ký tự có ý nghĩa đặc biệt khớp với chính nó, e. g. , ________ 1043 trận đấu ________ 1043, ________ 1045 trận đấu _____ 1045, v.v.

Một lần nữa, biểu thức phụ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

027 được sử dụng để khớp với tên miền email, có cùng mẫu với tên người dùng được mô tả ở trên

Biểu thức con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

048 khớp với một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5 theo sau là hai hoặc ba ký tự từ, e. g. , "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

050", "_______1051", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

052", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

053", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

054"

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

055 xác định rằng biểu thức con trên có thể xảy ra một hoặc nhiều lần, e. g. , "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

050", "______1057", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

058", v.v.

Tập thể dục. Giải thích biểu thức chính quy này, cung cấp một biểu diễn khác của địa chỉ email.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

059

Ví dụ. Hoán đổi từ bằng cách sử dụng Tham chiếu ngược được đặt trong ngoặc đơn ^[\S+]\s+[\S+]$ và $2 $1

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 lần lượt khớp với phần đầu và phần cuối của chuỗi đầu vào

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [chữ thường

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

063] khớp với khoảng trắng [trống, tab

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

09 và dòng mới

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08]. Mặt khác,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

067 [viết hoa

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

068] khớp với bất kỳ thứ gì KHÔNG khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062, tôi. e. , không có khoảng trắng. Trong regex, ký tự meta chữ hoa biểu thị nghịch đảo của ký tự chữ thường, ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85 cho ký tự từ và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071 cho ký tự không phải từ;

Regex trên khớp với hai từ [không có khoảng trắng] được phân tách bằng một hoặc nhiều khoảng trắng

Dấu ngoặc đơn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

074 có hai nghĩa trong regex

để nhóm các biểu thức con, e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

075

để cung cấp cái gọi là tham chiếu ngược để chụp và trích xuất kết quả khớp

Dấu ngoặc đơn trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076, được gọi là tham chiếu ngược được đặt trong ngoặc đơn, được sử dụng để trích xuất chuỗi con phù hợp từ chuỗi đầu vào. Trong biểu thức chính quy này, có hai

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076, khớp với hai từ đầu tiên, được phân tách bằng một hoặc nhiều khoảng trắng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

078. Hai từ phù hợp được trích xuất từ chuỗi đầu vào và thường được giữ trong các biến đặc biệt

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

130 [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

131 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

132 trong Python], tương ứng

Để hoán đổi hai từ, bạn có thể truy cập các biến đặc biệt và in "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

083" [thông qua ngôn ngữ lập trình];

Mã Ví dụ trong Python

Python giữ các tham chiếu ngược được đặt trong ngoặc đơn trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

131,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

132,. Ngoài ra,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

087 giữ toàn bộ trận đấu

Mã Ví dụ trong Java

Java giữ các tham chiếu ngược được đặt trong ngoặc đơn trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

130,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Ví dụ. Địa chỉ HTTP ^http. \/\/\S+[\/\S+]*[\/]?$

Bắt đầu bằng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

090. Hãy lưu ý rằng bạn có thể cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

091 thành

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

092 với mã thoát bằng một số ngôn ngữ [JavaScript, Perl]

Tiếp theo là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

067, một hoặc nhiều khoảng trắng, cho tên miền

Tiếp theo là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

094, không hoặc nhiều hơn "/. ", cho các thư mục con

Tiếp theo là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

095, một tùy chọn [0 hoặc 1] ở cuối

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

091, cho yêu cầu thư mục

Ví dụ. Các mẫu Regex trong AngularJS

Các mẫu biểu thức chính quy khá phức tạp sau đây được sử dụng bởi AngularJS theo cú pháp JavaScript

Ví dụ. Regex mẫu trong Perl

Cú pháp biểu thức chính quy [Regex]

Biểu thức chính quy [hoặc Regex] là một mẫu [hoặc bộ lọc] mô tả một tập hợp các chuỗi khớp với mẫu. Nói cách khác, một biểu thức chính quy chấp nhận một bộ chuỗi nhất định và từ chối phần còn lại

Một regex bao gồm một chuỗi các ký tự, siêu ký tự [chẳng hạn như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

073,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08s,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071] và các toán tử [chẳng hạn như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

07,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9]. Chúng được xây dựng bằng cách kết hợp nhiều biểu thức con nhỏ hơn

So khớp một ký tự

Các khối xây dựng cơ bản của biểu thức chính quy là các mẫu khớp với một ký tự. Hầu hết các ký tự, bao gồm tất cả các chữ cái [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

009 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

010] và chữ số [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

011], khớp với chính nó. Ví dụ: regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

11 khớp với chuỗi con

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

12;

Các ký tự không phải chữ và số không có ý nghĩa đặc biệt trong biểu thức chính quy cũng khớp với chính nó. Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

1 khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Các ký tự đặc biệt và chuỗi thoát của Regex

Ký tự đặc biệt của Regex

Các ký tự này có ý nghĩa đặc biệt trong regex [tôi sẽ trình bày chi tiết ở các phần sau]

siêu ký tự. dấu chấm [______05]

danh sách khung.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

023

vị trí neo.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

chỉ số xuất hiện. ________ 06, ________ 07, ________ 08, ________ 2029

dấu ngoặc đơn.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

128

hoặc.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

trốn thoát và siêu nhân vật. dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08]

trình tự thoát

Các ký tự được liệt kê ở trên có ý nghĩa đặc biệt trong regex. Để khớp các ký tự này, chúng ta cần thêm vào trước ký tự đó một dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08], được gọi là trình tự thoát. Ví dụ, ________ 202 khớp với ________ 203;

Regex cũng nhận ra các chuỗi thoát phổ biến như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 cho dòng mới,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

09 cho tab,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 cho ký tự xuống dòng,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

01 cho số bát phân có 3 chữ số,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

02 cho mã hex gồm hai chữ số,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

03 cho Unicode 4 chữ số,

Mã Ví dụ trong PythonVí dụ mã trong JavaScript

[LÀM]

Mã Ví dụ trong Java

[LÀM]

So khớp một chuỗi ký tự [Chuỗi hoặc Văn bản]

Biểu thức con

Một biểu thức chính quy được xây dựng bằng cách kết hợp nhiều biểu thức con hoặc nguyên tử nhỏ hơn. Ví dụ: regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

047 khớp với chuỗi "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

047". Theo mặc định, đối sánh phân biệt chữ hoa chữ thường nhưng có thể được đặt thành không phân biệt chữ hoa chữ thường thông qua công cụ sửa đổi

HOẶC [. ] Nhà điều hành

Bạn có thể cung cấp các lựa chọn thay thế bằng toán tử "HOẶC", được biểu thị bằng thanh dọc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

049. Ví dụ: regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

050 chấp nhận các chuỗi "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

051", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

052", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

053" hoặc "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

054"

Danh sách khung [Lớp ký tự] [. ], [^. ], [. -. ]

Biểu thức trong ngoặc là danh sách các ký tự được bao quanh bởi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

023, còn được gọi là lớp ký tự. Nó khớp với BẤT KỲ MỘT ký tự nào trong danh sách. Tuy nhiên, nếu ký tự đầu tiên của danh sách là dấu mũ [_______09], thì nó khớp với BẤT KỲ MỘT ký tự nào KHÔNG có trong danh sách. Ví dụ: regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

057 khớp với một chữ số duy nhất

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

41,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

059,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

054,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

061 hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062;

Thay vì liệt kê tất cả các ký tự, bạn có thể sử dụng một biểu thức phạm vi bên trong dấu ngoặc. Một biểu thức phạm vi bao gồm hai ký tự được phân tách bằng dấu gạch nối [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00]. Nó khớp với bất kỳ ký tự đơn nào sắp xếp giữa hai ký tự, bao gồm. Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

070 giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071. Bạn có thể bao gồm một dấu mũ [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9] trước phạm vi để đảo ngược kết quả khớp. Ví dụ, ________ 2073 tương đương với ________ 2074

Hầu hết các ký tự biểu thức chính quy đặc biệt đều mất ý nghĩa trong danh sách dấu ngoặc và có thể được sử dụng như hiện tại;

Để bao gồm một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

04, hãy đặt nó đầu tiên trong danh sách hoặc sử dụng thoát

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

080

Để bao gồm một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9, hãy đặt nó ở bất kỳ đâu trừ vị trí đầu tiên hoặc sử dụng thoát

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

082

Để bao gồm một ________ 500 đặt nó cuối cùng, hoặc sử dụng thoát _______ 2084

Để bao gồm một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08, hãy sử dụng thoát

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Không cần thoát cho các ký tự khác như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

01,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

02,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

05,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06, v.v., bên trong danh sách dấu ngoặc

Bạn cũng có thể bao gồm các siêu ký tự [sẽ được giải thích trong phần tiếp theo], chẳng hạn như ________ 085, ________ 1071, _______ 017, ________ 1073,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001 trong danh sách dấu ngoặc

Đặt tên cho các lớp ký tự trong danh sách ngoặc đơn [Chỉ dành cho Perl?]

Các lớp ký tự được đặt tên [POSIX] được xác định trước trong các biểu thức ngoặc. họ đang

________ 3001, ________ 3002, ________ 3003. chữ cái + chữ số, chữ cái, chữ số

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

004. chữ số thập lục phân

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

005,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

006. chữ thường/chữ hoa

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

007. Ký tự điều khiển

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

008. các ký tự có thể in được, ngoại trừ khoảng trắng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

009. các ký tự có thể in được, bao gồm khoảng trắng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

010. các ký tự có thể in được, không bao gồm các chữ cái và chữ số

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

011. khoảng trắng

Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

012 có nghĩa là

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

013. [Lưu ý rằng các dấu ngoặc vuông trong các tên lớp này là một phần của tên tượng trưng và phải được thêm vào cùng với các dấu ngoặc vuông phân định danh sách dấu ngoặc. ]

Siêu ký tự. , \w, \W, \d, \D, \s, \S

Siêu ký tự là một biểu tượng có ý nghĩa đặc biệt bên trong biểu thức chính quy

Dấu chấm siêu ký tự [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5] khớp với bất kỳ ký tự đơn nào ngoại trừ dòng mới

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

118]. Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

017 khớp với 3 ký tự bất kỳ [bao gồm bảng chữ cái, số, khoảng trắng, nhưng ngoại trừ xuống dòng];

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85 [ký tự từ] khớp với bất kỳ chữ cái, số hoặc dấu gạch dưới nào [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

120]. Đối tác chữ hoa

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071 [ký tự không phải từ] khớp với bất kỳ ký tự đơn nào không khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85 [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

026]

Trong regex, ký tự meta chữ hoa luôn là nghịch đảo của ký tự chữ thường

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17 [chữ số] khớp với bất kỳ chữ số nào [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06]. Đối tác chữ hoa

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

073 [không phải chữ số] khớp với bất kỳ ký tự đơn nào không phải là chữ số [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [dấu cách] khớp với bất kỳ khoảng trắng đơn nào [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

032, trống, tab, dòng mới, xuống dòng và nguồn cấp dữ liệu biểu mẫu]. Đối tác chữ hoa

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001 [không có dấu cách] khớp với bất kỳ ký tự đơn nào không khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [giống như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

035]

ví dụ

Dấu gạch chéo ngược [\] và chuỗi thoát Regex

Regex sử dụng dấu gạch chéo ngược [_______108] cho hai mục đích

đối với các siêu ký tự như

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17 [chữ số],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

073 [không phải chữ số],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [không gian],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001 [không phải khoảng trắng],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85 [từ],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071 [không phải từ]

để thoát khỏi các ký tự regex đặc biệt, e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 cho _______ 05, _______ 202 cho ________ 06, ________ 3047 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

049 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8. Bạn cũng cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 trong biểu thức chính quy để tránh sự mơ hồ

Regex cũng nhận ra

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08 cho dòng mới,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

09 cho tab, v.v.

Hãy lưu ý rằng trong nhiều ngôn ngữ lập trình [C, Java, Python], dấu gạch chéo ngược [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08] cũng được sử dụng cho các chuỗi thoát trong chuỗi, e. g. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

056 cho dòng mới,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

057 cho tab và bạn cũng cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

058 cho

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08. Do đó, để viết mẫu biểu thức chính quy

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

06 [khớp với một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

08] bằng các ngôn ngữ này, bạn cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [hai mức thoát. ]. Tương tự, bạn cần viết

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

063 cho siêu ký tự regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

17. Điều này là cồng kềnh và dễ bị lỗi

Chỉ số xuất hiện [Toán tử lặp lại]. +, *, ?, {m}, {m,n}, {m,}

Một biểu thức con regex có thể được theo sau bởi một chỉ báo xuất hiện [còn gọi là toán tử lặp lại]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8. Mục trước là tùy chọn và được khớp nhiều nhất một lần [i. e. , xảy ra 0 hoặc 1 lần hoặc tùy chọn]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

7. Mục trước đó sẽ được khớp từ 0 lần trở lên, tôi. e. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6. Mục trước đó sẽ được so khớp một hoặc nhiều lần, tôi. e. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

070. Mục trước được khớp chính xác m lần

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071. Mục trước được so khớp m lần trở lên, i. e. ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

117

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

073. Mục trước được so khớp ít nhất m lần, nhưng không quá n lần

Ví dụ. Regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

074 chấp nhận "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

075", "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076" và "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

077"

sửa đổi

Bạn có thể áp dụng các công cụ sửa đổi cho biểu thức chính quy để điều chỉnh hành vi của nó, chẳng hạn như toàn cầu, phân biệt chữ hoa chữ thường, nhiều dòng, v.v. Các cách áp dụng công cụ sửa đổi khác nhau giữa các ngôn ngữ

Trong Perl, bạn có thể đính kèm các công cụ sửa đổi sau biểu thức chính quy, ở dạng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

078. Ví dụ như

Trong Java, bạn áp dụng các công cụ sửa đổi khi biên dịch regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

079. Ví dụ,

Các chế độ bổ trợ thường được sử dụng là

Chế độ không phân biệt chữ hoa chữ thường [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

010]. khớp không phân biệt chữ hoa chữ thường cho các chữ cái

Toàn cầu [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

081]. khớp Tất cả thay vì khớp đầu tiên

Chế độ nhiều dòng [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

113]. ảnh hưởng đến

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

085 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

086. Trong chế độ nhiều dòng,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 khớp với đầu dòng hoặc đầu đầu vào;

Chế độ một dòng [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

063]. Dấu chấm [

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

5] sẽ khớp với tất cả các ký tự, bao gồm cả dòng mới

Chế độ nhận xét [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

11]. cho phép và bỏ qua nhận xét được nhúng bắt đầu bằng

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

094 cho đến cuối dòng [EOL]

hơn

Tham lam, lười biếng và quay lui cho các toán tử lặp lại

Sự tham lam của các toán tử lặp lại *, +, ?, {m,n}. Các toán tử lặp lại là các toán tử tham lam và theo mặc định nắm bắt càng nhiều ký tự càng tốt cho một kết quả khớp. Ví dụ: biểu thức chính quy

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

074 cố gắng khớp với "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

077", sau đó là "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076" và sau đó là "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

075"

Định lượng lười biếng *?, +?, ??, {m,n}?, {m,}?,. Bạn có thể đặt thêm một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

8 sau các toán tử lặp lại để hạn chế tính tham lam của nó [i. e. , dừng lại ở trận đấu ngắn nhất]. Ví dụ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

quay lui. Nếu một biểu thức chính quy đạt đến trạng thái không thể hoàn thành một trận đấu, thì nó sẽ quay lại bằng cách hủy một ký tự khỏi trận đấu tham lam. Ví dụ: nếu regex

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

000 khớp với chuỗi "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001", thì

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

002 đầu tiên khớp với "

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

001";

Lượng từ sở hữu *+, ++, ?+, {m,n}+, {m,}+. Bạn có thể đặt thêm một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

6 cho các toán tử lặp lại để tắt tính năng quay lui, thậm chí nó có thể dẫn đến lỗi khớp. e. g,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

008 sẽ không khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

009. Tính năng này có thể không được hỗ trợ ở một số ngôn ngữ

Position Anchors ^, $, \b, \B, \, \A, \Z

Các neo vị trí KHÔNG khớp với ký tự thực, nhưng khớp với vị trí trong một chuỗi, chẳng hạn như đầu dòng, cuối dòng, đầu từ và cuối từ

^ và $.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 khớp với đầu dòng.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 khớp với cuối dòng không bao gồm dòng mới hoặc cuối đầu vào [đối với đầu vào không kết thúc bằng dòng mới]. Đây là những neo vị trí được sử dụng phổ biến nhất. Ví dụ như,

\b và \B.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

125 khớp với ranh giới của một từ [i. e. , đầu từ hoặc cuối từ]; . Ví dụ như,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

015 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

016.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

015 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

016 lần lượt khớp với phần đầu và phần cuối của từ [so với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

125, có thể khớp với cả phần đầu và phần cuối của một từ]

\A và \Z.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

085 khớp với phần đầu của đầu vào.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

086 khớp với phần cuối của đầu vào.
Chúng khác với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 khi khớp đầu vào với nhiều dòng.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

9 khớp ở đầu chuỗi và sau mỗi lần ngắt dòng, trong khi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

085 chỉ khớp ở đầu chuỗi.

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

00 khớp ở cuối chuỗi và trước mỗi lần ngắt dòng, trong khi

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

086 chỉ khớp ở cuối chuỗi. Ví dụ,

Nắm bắt kết quả phù hợp thông qua tham chiếu ngược được đặt trong ngoặc đơn & biến phù hợp $1, $2,

Dấu ngoặc đơn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

128 phục vụ hai mục đích trong regex

Đầu tiên, dấu ngoặc đơn

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

128 có thể được sử dụng để nhóm các biểu thức con nhằm ghi đè quyền ưu tiên hoặc áp dụng toán tử lặp lại. Ví dụ,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

030 [chấp nhận

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

43,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

032,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

033,. ] khác với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

034 [chấp nhận

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

43,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

036,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

037,. ]

Thứ hai, dấu ngoặc đơn được sử dụng để cung cấp cái gọi là tham chiếu ngược [hoặc nhóm chụp]. Tham chiếu ngược chứa chuỗi con phù hợp. Ví dụ: biểu thức chính quy

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076 tạo một tham chiếu ngược

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076, chứa từ đầu tiên [không phải khoảng trắng liên tiếp] của chuỗi đầu vào; .

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076 và một

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

076 khác, chứa hai từ đầu tiên, được phân tách bằng một hoặc nhiều dấu cách

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

078

Các tham chiếu ngược này [hoặc các nhóm chụp] được lưu trữ trong các biến đặc biệt

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

130, … [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

131,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

132,. trong Python], trong đó

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129chứa chuỗi con khớp với cặp dấu ngoặc đơn đầu tiên, v.v. Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

040 tạo hai tham chiếu ngược khớp với hai từ đầu tiên. Các từ phù hợp được lưu trữ lần lượt trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

129 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

130 [hoặc

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

131 và

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

132]

Tham chiếu ngược rất quan trọng để thao tác chuỗi. Tham chiếu ngược có thể được sử dụng trong chuỗi thay thế cũng như mẫu. Ví dụ như,

[Nâng cao] Lookahead/Lookbehind, Groupings và Conditional

Tính năng này có thể không được hỗ trợ ở một số ngôn ngữ

Cái nhìn tích cực [?=mẫu]

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

054 được gọi là cái nhìn tích cực. Nó thực hiện khớp, nhưng không bắt được khớp, chỉ trả về kết quả. phù hợp hoặc không phù hợp. Nó còn được gọi là xác nhận vì nó không sử dụng bất kỳ ký tự nào trong khớp. Ví dụ: biểu thức chính quy phức tạp sau đây được sử dụng để khớp với địa chỉ email của AngularJS

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Các mẫu tìm kiếm tích cực đầu tiên

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

055 đặt độ dài tối đa thành 254 ký tự. Cái nhìn tích cực thứ hai

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

056 đặt tối đa 64 ký tự trước dấu hiệu

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

057 cho tên người dùng

Cái nhìn tiêu cực [?. mẫu]

Nghịch đảo của

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

054. Khớp nếu thiếu

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

059. Ví dụ:

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

060 khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

061 trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

062 [không tiêu thụ

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

063]; . Trong khi đó

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

065 khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

061 trong

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

064, nhưng không khớp với

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

Giao diện tích cực [? mẫu]

Vô hiệu hóa quay lui, ngay cả khi điều này có thể dẫn đến lỗi đối sánh

Điều kiện [?[Cond]then. khác]

[LÀM]

bảng chữ cái

Các siêu ký tự

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

85,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

071, [từ và ký tự không phải từ],

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

125,

find[] found substring "00123" starting at index 3 and ending at index 8
find[] found substring "456" starting at index 11 and ending at index 14
find[] found substring "0" starting at index 15 and ending at index 16
matches[] found nothing
lookingAt[] found nothing
abc**xyz456_0
abc++xyz++_++

013 [ranh giới từ và không phải từ] nhận dạng lại các ký tự Unicode

?= * Có nghĩa là gì trong regex?

?= là một cái nhìn tích cực, một loại xác nhận có độ rộng bằng 0 . Điều nó nói là trận đấu được bắt phải được theo sau bởi bất cứ điều gì trong ngoặc đơn nhưng phần đó không được bắt. Ví dụ của bạn có nghĩa là trận đấu cần phải được theo sau bởi 0 hoặc nhiều ký tự và sau đó là một chữ số [nhưng một lần nữa, phần đó không được ghi lại].

Có * khớp với mọi thứ trong regex không?

Nhập dấu * [dấu hoa thị] và nó sẽ khớp với mọi thứ . Đọc thêm. \s [siêu ký tự khoảng trắng] sẽ khớp với bất kỳ ký tự khoảng trắng nào [dấu cách; tab; ngắt dòng;. ] và \S [ngược lại với \s ] sẽ khớp với bất kỳ thứ gì không phải là ký tự khoảng trắng.

\b trong regex là gì?

Ranh giới từ \b khớp với các vị trí trong đó một bên là ký tự từ [thường là một chữ cái, chữ số hoặc dấu gạch dưới—nhưng hãy xem bên dưới để biết các biến thể giữa các công cụ] và bên còn lại là . [for instance, it may be the beginning of the string or a space character].

Khớp mẫu regex là gì?

Biểu thức chính quy là mẫu mà công cụ biểu thức chính quy cố gắng khớp với văn bản đầu vào . Một mẫu bao gồm một hoặc nhiều ký tự, toán tử hoặc cấu trúc.

Regex theo ví dụ

Tóm tắt cú pháp Regex

Ví dụ. Số [0-9]+ hoặc \d+

Ví dụ về mã [Python, Java, JavaScript, Perl, PHP]

Ví dụ. Chuỗi số đầy đủ ^[0-9]+$ hoặc ^\d+$

Ví dụ. Số nguyên dương [1-9][0-9]*. 0 hoặc [1-9]\d*. 0

Ví dụ. Chữ số nguyên đầy đủ ^[+-]?[1-9][0-9]*. 0$ hoặc ^[+-]?[1-9]\d*. 0$

Ví dụ. Mã định danh [hoặc Tên] [a-zA-Z_][0-9a-zA-Z_]* hoặc [a-zA-Z_]\w*

Ví dụ. Tên tệp hình ảnh ^\w+\. [gif. png. jpg. jpeg]$

Ví dụ. Địa chỉ email ^\w+[[. -]?\w+]*@\w+[[. -]?\w+]*[\. \w{2,3}]+$

Ví dụ. Hoán đổi từ bằng cách sử dụng Tham chiếu ngược được đặt trong ngoặc đơn ^[\S+]\s+[\S+]$ và $2 $1

Ví dụ. Địa chỉ HTTP ^http. \/\/\S+[\/\S+]*[\/]?$

Ví dụ. Các mẫu Regex trong AngularJS

Ví dụ. Regex mẫu trong Perl

Cú pháp biểu thức chính quy [Regex]

So khớp một ký tự

Các ký tự đặc biệt và chuỗi thoát của Regex

So khớp một chuỗi ký tự [Chuỗi hoặc Văn bản]

HOẶC [. ] Nhà điều hành

Danh sách khung [Lớp ký tự] [. ], [^. ], [. -. ]

Siêu ký tự. , \w, \W, \d, \D, \s, \S

Dấu gạch chéo ngược [\] và chuỗi thoát Regex

Chỉ số xuất hiện [Toán tử lặp lại]. +, *, ?, {m}, {m,n}, {m,}

sửa đổi

Tham lam, lười biếng và quay lui cho các toán tử lặp lại

Position Anchors ^, $, \b, \B, \, \A, \Z

Nắm bắt kết quả phù hợp thông qua tham chiếu ngược được đặt trong ngoặc đơn & biến phù hợp $1, $2,

[Nâng cao] Lookahead/Lookbehind, Groupings và Conditional

bảng chữ cái

?= * Có nghĩa là gì trong regex?

Có * khớp với mọi thứ trong regex không?

\b trong regex là gì?

Khớp mẫu regex là gì?

Bài Viết Liên Quan

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Chủ Đề

Ví dụ. Số nguyên dương [1-9][0-9]. 0 hoặc [1-9]\d. 0

Ví dụ. Chữ số nguyên đầy đủ ^[+-]?[1-9][0-9]. 0$ hoặc ^[+-]?[1-9]\d. 0$

Ví dụ. Địa chỉ email ^\w+[[. -]?\w+]@\w+[[. -]?\w+][\. \w{2,3}]+$