PHP 8 reference · Array Functions

PHP array_find_key() Function

Return the key of the first element for which a callback returns true, or null if none match. Added in PHP 8.4.

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Syntax

array_find_key(array $array, callable $callback): mixed

Parameter	Description
`array`	The input array.
`callback`	`fn($value, $key)` returns `true` for a match.

The first matching key, or null.

Which item is out of stock?

<?php
$stock = ["tea" => 12, "cake" => 0, "milk" => 4];
echo array_find_key($stock, fn($qty) => $qty === 0), "\n";

Output

cake

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No match

<?php
var_dump(array_find_key(["x", "y"], fn($v) => $v === "z"));

Output

NULL

Run this on your computer — see “Get Started” for setup.

Version	Change
PHP 8.4	Added

array_find() · Return the first element for which a callback returns true, or null if none match. Added in PHP 8.4.
array_search() · Search an array for a value and return the first matching key, or false if it isn't there.
PHP Array Functions · tutorial
PHP Arrays · tutorial