Learning PHP
Advanced PHP
PHP Function Reference
PHP Useful Resources
Selected Reading
© 2011 TutorialsPoint.COM
|
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 )
|
|
|
|