PHP - Function uasort()


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Syntax

uasort ( $array, $cmp_function )

Definition and Usage

This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant. The comparison function is user-defined.

Parameters

Parameter Description
array Required. Specifies an array.
cmp_function

Required. Use if 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;
   }
   
   $fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana" );
   uasort($fruits, "cmp_function");
   
   print_r($fruits);
?> 

This will produce the following result −

Array ( [a] => orange [d] => lemon [b] => banana )

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