(PHP 5 >= 5.1.0, PHP 7, PHP 8)
array_intersect_key — Computes the intersection of arrays using keys for comparison
$array, array ...$arrays): array
array_intersect_key() returns an array
containing all the entries of array
which have keys that are present in all the arguments.
arrayThe array with master keys to check.
arraysArrays to compare keys against.
Returns an associative array containing all the entries of
array which have keys that are present in all
arguments.
Example #1 array_intersect_key() example
<?php
$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));
?>
The above example will output:
array(2) {
["blue"]=>
int(1)
["green"]=>
int(3)
}
In our example you see that only the keys 'blue'
and 'green' are present in both arrays and thus
returned. Also notice that the values for the keys
'blue' and 'green' differ between
the two arrays. A match still occurs because only the keys are checked.
The values returned are those of array.
The two keys from the key => value pairs are
considered equal only if
(string) $key1 === (string) $key2 . In other words
a strict type check is executed so the string representation must be
the same.