- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$subject = '512345678';
$pattern = '/^(?:
[12]\d{6,8}|
[3-57-9]\d{8}|
6\d{5,8}
)$/x';
$result = preg_match($pattern, $subject, $groups, PREG_OFFSET_CAPTURE);
var_dump($result, $groups);