- var_dump: documentation ( source)
- preg_match: documentation ( source)
- var_export: documentation ( source)
- preg_quote: documentation ( source)
<?php
$kw = " asdsdfsdf as ";
$pattern = '/[' . preg_quote(',!@%^*()={};~`<>?\|', '/') . ']/u';
var_dump($pattern, var_export($pattern));
var_dump(preg_match($pattern, $kw));