- var_dump: documentation ( source)
- array_flip: documentation ( source)
- array_diff_key: documentation ( source)
<?php
$a = array('a' => 1, 'b' => 2);
$b = array('a', 'b');
$result = array_diff_key($a, array_flip($b));
$is_empty = empty($result);
var_dump($is_empty);