- var_dump: documentation ( source)
- preg_replace: documentation ( source)
<?php
var_dump(preg_replace("/^[^a-zA-Z]+|[\!\#$\%\&\'\* \+\/\=\?\^\`{\|\}\~]+/", "",'_(32jkashdfkj$@#!!&&'));
var_dump( preg_replace( '|[^a-z0-9_.\-@]|i', '', '_(32jkashdfkj$#!!&&' ));