- var_dump: documentation ( source)
- preg_match: documentation ( source)
- preg_quote: documentation ( source)
<?php
var_dump(!!preg_match('#\\b' . preg_quote("no", '#') . '\\b#i', "No.") || !!preg_match('#\\b' . preg_quote("No", '#') . '\\b#i', "No."));