PHP Function usort()

Syntax

usort ( $array, $cmp_function )

Definition and Usage

The usort() function sorts an array by a user defined comparison function. This function assigns new keys for the elements in the array. Existing keys will be removed.

Paramters

Parameter	Description
array	Required. Specifies an array.
cmp_function	Required. Usef defined function to compare values and to sort them. The function must return -1, 0, or 1 for this method to work correctly. It should be written to accept two parameters to compare, and it should work something like this: If a = b, return 0 If a > b, return 1 If a < b, return -1

Return Value

Returns TRUE on success or FALSE on failure.

Example

Try out following example:

<?php function cmp_function($a, $b) { if ($a == $b) return 0; return ($a > $b) ? -1 : 1; } $fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana" ); usort($fruits, "cmp_function"); print_r($fruits); ?>

This will produce following result:

Array ( [0] => orange [1] => lemon [2] => banana )