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Đôi khi, nhiều hơn là tìm một chuỗi con, chúng ta có thể cần phải có được chuỗi đang xảy ra trước khi tìm thấy chuỗi con. Hãy để thảo luận về những cách nhất định trong đó nhiệm vụ này có thể được thực hiện.
Python3
Phương pháp số 1: Sử dụng phân vùng [] & nbsp;
Chức năng phân vùng có thể được sử dụng để thực hiện nhiệm vụ này, trong đó chúng tôi chỉ trả về một phần của phân vùng xảy ra trước từ phân vùng.
test_string
=
"GeeksforGeeks is best for geeks"
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is0
=
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is2
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is5
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is7
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is8
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is1
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is7
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
5=
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
7The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
8The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
9
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is
The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
3The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
4s = "wolfdo65gtornado!salmontiger223" + some_other_string
2 The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
6 s = "wolfdo65gtornado!salmontiger223" + some_other_string
4Method #2 : Using split[]
s = "wolfdo65gtornado!salmontiger223" + some_other_string
s = "wolfdo65gtornado!salmontiger223" + some_other_string
Đầu ra: & nbsp;
Python3
Phương pháp số 1: Sử dụng phân vùng [] & nbsp;
Chức năng phân vùng có thể được sử dụng để thực hiện nhiệm vụ này, trong đó chúng tôi chỉ trả về một phần của phân vùng xảy ra trước từ phân vùng.
test_string
=
"GeeksforGeeks is best for geeks"
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is0
=
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is2
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is5
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is7
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is8
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is1
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is7
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
5=
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
7The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
8The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
9
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is
The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
3The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
4s = "wolfdo65gtornado!salmontiger223" + some_other_string
2 The original string : GeeksforGeeks is best for geeks
The split string : best
String before the substring occurrence : GeeksforGeeks is
6 s = "wolfdo65gtornado!salmontiger223" + some_other_string
4
s = "wolfdo65gtornado!salmontiger223" + some_other_string
s = "wolfdo65gtornado!salmontiger223" + some_other_string
Python3
Phương pháp số 1: Sử dụng phân vùng [] & nbsp;
Chức năng phân vùng có thể được sử dụng để thực hiện nhiệm vụ này, trong đó chúng tôi chỉ trả về một phần của phân vùng xảy ra trước từ phân vùng.
test_string
=
"GeeksforGeeks is best for geeks"
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is0
=
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is2
test_string
8=
=
0
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is8
=
2The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is1
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is7
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is4
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
5=
The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
7The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
8The original string : GeeksforGeeks is best for geeks
String before the substring occurrence : GeeksforGeeks is
9
The original string : GeeksforGeeks is best for geeks String before the substring occurrence : GeeksforGeeks is
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is3
The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is4
s = "wolfdo65gtornado!salmontiger223" + some_other_string
2 The original string : GeeksforGeeks is best for geeks The split string : best String before the substring occurrence : GeeksforGeeks is6
s = "wolfdo65gtornado!salmontiger223" + some_other_string
4Đầu ra: & nbsp;O[n]
& nbsp; Phương thức #2: Sử dụng split [] & nbsp;O[n]
Giả sử chúng ta có:
s = "wolfdo65gtornado!salmontiger223" + some_other_string
=
8 và =
9 đều là một vấn đề nếu "GeeksforGeeks is best for geeks"
0 chứa một triệu chuỗi, mỗi chuỗi dài một triệu ký tự, cách nhau bởi các dấu chấm than. Tôi đề nghị những điều sau đây thay thế. Nó hiệu quả hơn nhiều.
import itertools as itts
get_start_of_string = lambda stryng, last, *, itts=itts:\
str[itts.takewhile[lambda ch: ch != last, stryng]]
###########################################################
s = "wolfdo65gtornado!salmontiger223"
start_of_string = get_start_of_string[s, "!"]
Tại sao "GeeksforGeeks is best for geeks"
1
Bên trong cơ thể của một chức năng, chẳng hạn như "GeeksforGeeks is best for geeks"
2, "GeeksforGeeks is best for geeks"
3 là toàn cầu. "GeeksforGeeks is best for geeks"
3 được đánh giá khi hàm được gọi, không phải khi hàm được xác định. Xem xét ví dụ sau:
"GeeksforGeeks is best for geeks"
3 is evaluated when the function is called, not when the function is
defined.
Consider the following example:
color = "white"
get_fleece_color = lambda shoop: shoop + ", whose fleece was as " + color + " as snow."
print[get_fleece_color["Igor"]]
# [... many lines of code later...]
color = "pink polka-dotted"
print[get_fleece_color["Igor's cousin, 3 times removed"]]
Đầu ra là:
Igor, whose fleece was white as snow.
Igor's cousin, 3 times removed Igor, whose fleece was as pink polka-dotted as snow.