- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$str[] = "3543900000133243";
$str[] = "3543sssssxxxxxx23243";
$str[] = "1543344=-23-1--923243";
$pattern = "/\A3543(.+)3243\Z/";
foreach($str as $key=>$string) {
echo preg_match($pattern,$string,$res);
var_dump($res);
}