- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$str1 = "3543900000133243";
$str2 = "354334494923243";
$str3 = "154334494923243";
echo preg_match("/\A3543.+3243\Z/",$str1,$res);
var_dump($res);
echo preg_match("/\A3543.+3243\Z/",$str2,$res);
var_dump($res);
echo preg_match("/\A3543.+3243\Z/",$str3,$res);
var_dump($res);