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ArrayObject::uasort

PHP function Edit on GitHub ✎

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

Sort the entries with a user-defined comparison function and maintain key association

Description

ArrayObject::uasort(callable $callback): true

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.

Sort-unstable

Parameters

callback: Description

Return Values

Always

Changelog

Version	Description

Examples

ArrayObject::uasort() example

php

<?php
// Comparison function
function 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);
var_dump($arrayObject);

// Sort and print the resulting array
$arrayObject->uasort('cmp');
var_dump($arrayObject);
?>

The above example will output:

output

object(ArrayObject)#1 (1) {
  ["storage":"ArrayObject":private]=>
  array(8) {
    ["a"]=>
    int(4)
    ["b"]=>
    int(8)
    ["c"]=>
    int(-1)
    ["d"]=>
    int(-9)
    ["e"]=>
    int(2)
    ["f"]=>
    int(5)
    ["g"]=>
    int(3)
    ["h"]=>
    int(-4)
  }
}
object(ArrayObject)#1 (1) {
  ["storage":"ArrayObject":private]=>
  array(8) {
    ["d"]=>
    int(-9)
    ["h"]=>
    int(-4)
    ["c"]=>
    int(-1)
    ["e"]=>
    int(2)
    ["g"]=>
    int(3)
    ["a"]=>
    int(4)
    ["f"]=>
    int(5)
    ["b"]=>
    int(8)
  }
}