- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$str = "Faktura č.: XYZ";
preg_match("~^\\s*Faktura\\s+č.:\\s*(?P<invoice>\S+)(?:\\s+za\\s+období\\s+0?(?P<month>\\d{1,2})\\s*/\\s*(?P<year>\\d{4}))?\\s*$~iu", $str, $matches);
var_dump($matches);