- var_dump: documentation ( source)
- preg_match_all: documentation ( source)
<?php
$matches = array();
var_dump(preg_match_all('/[^a-zA-Z0-9.-\s]+/', '[[-?)', $matches));
var_dump($matches);
$matches = array();
var_dump(preg_match_all('/[^a-zA-Z0-9.\-\s]+/', '[[-?)', $matches));
var_dump($matches);