php man page for uksort

UKSORT(3)								 1								 UKSORT(3)

uksort - Sort an array by keys using a user-defined comparison function

SYNOPSIS
       bool uksort (array  &$array, callable  $key_compare_func)

DESCRIPTION
       uksort(3)  will	sort  the  keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by
       some non-trivial criteria, you should use this function.

PARAMETERS
	      o $array
		- The input array.

	      o $key_compare_func
		- The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered	to
		be respectively less than, equal to, or greater than the second.
		int callback (mixed  $a, mixed	$b)

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

EXAMPLES
       Example #1

	      uksort(3) example

	      <?php
	      function cmp($a, $b)
	      {
		  $a = preg_replace('@^(a|an|the) @', '', $a);
		  $b = preg_replace('@^(a|an|the) @', '', $b);
		  return strcasecmp($a, $b);
	      }

	      $a = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4);

	      uksort($a, "cmp");

	      foreach ($a as $key => $value) {
		  echo "$key: $value
";
	      }
	      ?>

	      The above example will output:

	      an apple: 3
	      a banana: 4
	      the Earth: 2
	      John: 1

SEE ALSO
       usort(3), The comparison of array sorting functions.

PHP Documentation Group 														 UKSORT(3)