- array_intersect_key: documentation ( source)
- print_r: documentation ( source)
<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue");
$array2 = array("a" => "green", "c" => "blue2", "d" => "cyan");
$array1 = array_intersect_key($array1, $array2);
print_r($result);
$result = array_intersect_key($array2, $array1);
print_r($result);