- var_dump: documentation ( source)
- strrpos: documentation ( source)
- mb_strrpos: documentation ( source)
<?php
$text = "01-3-567-90";
var_dump(strrpos($text, "-") , mb_strrpos($text, "-"));
var_dump(strrpos($text, "-", 7) , mb_strrpos($text, "-", 7));
var_dump(strrpos($text, "-", -4), mb_strrpos($text, "-", -4));