3v4l.org

run code in 300+ PHP versions simultaneously
<?php $required = ['foo' => '', 'bar' => '']; $optional = ['baz' => '']; $data = ['foo' => '', 'baz' => '', 'sadsads' => '']; var_dump(array_diff_key($required + $optional, $data));

preferences:
51.06 ms | 402 KiB | 5 Q