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.

Parameters

Sr.No	Parameter & Description
1	array(Required) It specifies an array.
2	cmp_function(Required) Useful defined function to compare values and to sort them. If a = b, return 0 If a > b, return 1 If a < b, return -1

Sr.No

Parameter & Description

array(Required)

It specifies an array.

cmp_function(Required)

Useful defined function to compare values and to sort them.

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 the following result −

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

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PHP - Function usort()

Syntax

Definition and Usage

Parameters

Return Value

Example