Sort the elements of an array by their values using a user-defined comparison function.
| <?php function my_sort($a, $b) { if ($a == $b) return 0; return ($a < $b) ? –1 : 1; } $a = array(4, 2, 8, 6); usort($a, “my_sort”); foreach($a as $key => $value) { echo “[“ . $key . “] => “ . $value; echo “<br>”; } ?> |
The usort() function sorts an array by its values using a user-defined comparison function.
Tip: Use the uksort() function to sort an array by its keys with a user-defined comparison function.
Tip: Use the uasort() function to sort an array by its values while preserving index associations, using a user-defined comparison function.
| usort(array, callback) |
|
Parameter |
Description |
|
array |
Required. Specifies the array to be sorted. |
|
callback |
Required. A comparison function that must return an integer less than, equal to, or greater than 0 if the first argument is less than, equal to, or greater than the second argument. |
|
Return Value: |
Always returns |
|
PHP Version: |
4+ |
|
PHP Changelog: |
PHP 8.2.0: Now returns PHP 8.0.0: If the callback expects a parameter to be passed by reference, it now triggers an |