- var_dump: documentation ( source)
- in_array: documentation ( source)
<?php
var_dump(in_array(42, ['42 hours']));
var_dump(in_array(42, ['42 hours'], true));
var_dump(in_array('', [0]));
var_dump(in_array('dont care', [0]));
var_dump(in_array('', [0], true));