PHP usort() Function
Example
Sort the elements of the array $a using a user-defined comparison function:
<?php
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a<$b)?-1:1;
}
$a=array(4,2,8,6);
usort($a,"my_sort");
?>
Definition and Usage
usort() sorts an array using a user-defined comparison function.
Syntax
usort(array,myfunction);
| Parameter | Description |
|---|---|
| array | Required. Specifies the array to be sorted. |
| myfunction | Optional. Defines a string that specifies the name of a callable comparison function. If the first argument is less than, equal to, or greater than the second argument, the comparison function must return an integer less than, equal to, or greater than 0. |
Description
usort() function sorts an array using a user-defined function.
Note:If two elements have the same comparison result, the order of these elements in the sorted array is undefined. Before PHP 4.0.6, user-defined functions would retain the original order of these elements. However, due to the introduction of a new sorting algorithm in 4.1.0, the result will not be as expected because there is no effective solution for this.
Note:This function is array Assigns a new key name to the elements within. This will remove the original key names.
Technical Details
| Return Value: | Returns TRUE if successful, FALSE otherwise. |
| PHP Version: | 4+ |
