In this article, you will learn how to sort an array based on some user-defined function. The usort() function compares array elements by passing them to the user-defined function and sorts them according to the comparison result.
What is the syntax of the usort() function in PHP?
usort(array, myfunction)| Parameter | Details |
|---|---|
| array | The array to sort – Required |
| my_function | Callable function name (string). The callable function compares two values and returns an integer <, =, or > 0 if the first value is <, = or > than second. |
Examples of usort() function
Example 1. Sort the array elements using the user-defined function.
<?php
function my_function($x,$y)
{
if ($x==$y) return 0;
return ($x<$y)?-1:1;
}
$arr=array(3,15,21,9,86);
usort($arr,"my_function");
?>
