ArrayObject::uasort

(PHP 5 >= 5.2.0, PHP 7)

ArrayObject::uasortSort the entries with a user-defined comparison function and maintain key association


Description

public ArrayObject::uasort ( callable $cmp_function ) : void

This function sorts the entries such that keys maintain their correlation with the entry that they are associated with, using a user-defined comparison function.

This is used mainly when sorting associative arrays where the actual element order is significant.


Parameters

cmp_function
Function cmp_function should accept two parameters which will be filled by pairs of entries. 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.


Return Values

No value is returned.


Examples

Example #1 ArrayObject::uasort() example

<?php// Comparison functionfunction cmp($a, $b) {    if ($a == $b) {        return 0;    }    return ($a < $b) ? -1 : 1;}// Array to be sorted$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);$arrayObject = new ArrayObject($array);print_r($arrayObject);// Sort and print the resulting array$arrayObject->uasort('cmp');print_r($arrayObject);?>

The above example will output:


Array
(
    [a] => 4
    [b] => 8
    [c] => -1
    [d] => -9
    [e] => 2
    [f] => 5
    [g] => 3
    [h] => -4
)
Array
(
    [d] => -9
    [h] => -4
    [c] => -1
    [e] => 2
    [g] => 3
    [a] => 4
    [f] => 5
    [b] => 8
)

See Also