Hướng dẫn array iteration in php
(PHP 4, PHP 5, PHP 7, PHP 8) The foreach (iterable_expression as $value) statement foreach (iterable_expression as $key => $value) statement The first form traverses the iterable given by The second form will additionally assign the current element's key to the Note that It is possible to customize object iteration. In order to be able to directly modify array elements within the loop precede
Warning Reference of a
foreach ($arr as $key => $value) { It is possible to iterate a constant array's value by reference:
Some more examples to demonstrate usage:
$a as $v) { Unpacking nested arrays with list()(PHP 5 >= 5.5.0, PHP 7, PHP 8) It is possible to iterate over an array of arrays and unpack the nested array into loop variables by providing a list() as the value. For example:
$array as list($a, $b)) { The above example will output: You can provide fewer elements in the list() than there are in the nested array, in which case the leftover array values will be ignored:
$array as list($a)) { The above example will output: A notice will be generated if there aren't enough array elements to fill the list():
$array as list($a, $b, $c)) { The above example will output: Notice: Undefined offset: 2 in example.php on line 7 A: 1; B: 2; C: Notice: Undefined offset: 2 in example.php on line 7 A: 3; B: 4; C: There are no user contributed notes for this page. |