PHP 8 reference · Array Sorting Functions

PHP krsort() Function

Sort an array by key in descending order, keeping each value with its key.

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Syntax

krsort(array &$array, int $flags = SORT_REGULAR): true

Parameter	Description
`array`	The array to sort (changed in place).
`flags` optional	`SORT_REGULAR`, `SORT_NUMERIC`, `SORT_STRING`, `SORT_NATURAL`, optionally `\| SORT_FLAG_CASE`. Default: `SORT_REGULAR`

Always true.

Newest date firstTry it yourself

<?php
$events = ["2024-05-01" => "launch", "2026-01-10" => "v2", "2025-03-15" => "beta"];
krsort($events);
print_r($events);

Output

Array
(
    [2026-01-10] => v2
    [2025-03-15] => beta
    [2024-05-01] => launch
)

Numeric keysTry it yourself

<?php
$sizes = [10 => "M", 2 => "XS", 14 => "L"];
krsort($sizes);
echo implode(", ", $sizes), "\n";

Output

L, M, XS

Version	Change
PHP 4.0	Added
PHP 8.0	Sorting is stable: elements that compare equal keep their original order.
PHP 8.2	The return type is `true` (it was `bool`).

ksort() · Sort an array by key in ascending order, keeping each value with its key.
arsort() · Sort an array by value in descending order, keeping each key attached to its value. Great for leaderboards.
rsort() · Sort an array's values in descending order, in place. Keys are discarded and the result is renumbered from 0.
PHP Arrays · tutorial
PHP Array Functions · tutorial