PHP usort() Function

Definition and Usage

The usort() function sorts an array using a user-defined comparison function.

Syntax

usort(array,function);

Parameter Description
array Required. Specifies the array to sort
function Optional. A string that define a callable comparison function. The comparison function must return an integer <, =, or > than 0 if the first argument is <, =, or > than the second argument

Example

Sort the elements of the $a array using a user-defined comparison function:
<?php
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a<$b)?-1:1;
}

$a=array(4,2,8,6);
usort($a,"my_sort");
?> 
 
OUTPUT :