array_intersect_key()

array_intersect_key() — Computes the intersection of arrays using keys for comparison.

Built-in function of PHP 8.5. The manual lists it as available in PHP 5 >= 5.1.0, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

array_intersect_key() returns an array containing all the entries of array which have keys that are present in all the arguments.

Signature

array_intersect_key(array $array, array ...$arrays): array

Parameters

Return value

Returns an associative array containing all the entries of array which have keys that are present in all arguments.

Example

A runnable snippet:

$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4); $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8); var_dump(array_intersect_key($array1, $array2));

Output:

array(2) { ["blue"]=> int(1) ["green"]=> int(3) }

Changelog

See also

array_diff(), array_udiff(), array_diff_assoc(), array_diff_uassoc(), array_udiff_assoc(), array_udiff_uassoc(), array_diff_key(), array_diff_ukey(), array_intersect(), array_intersect_assoc(), array_intersect_uassoc(), array_intersect_ukey()

All PHP 8.5 built-in functions

Reference card built from the PHP manual page array_intersect_key() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.