- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$string = '中文';
preg_match('/^[\pL\pM\pN_-]+$/u', $string, $matches1); // laravel style
preg_match('/^[a-z0-9_-]+$/u', $string, $matches2);
var_dump($matches1);
var_dump($matches2);