- array_intersect_key: documentation ( source)
- print_r: documentation ( source)
<?php
$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6);
print_r(array_intersect_key($array1, $array2));
?>