$re = '/^([0-9]{3})-?([0-9]{3})-?([0-9]{3})-?(?<LAST>[0-9]{3})?(?(<LAST>)<LAST>)$/m';
$str = '009026405
01009556500
226-356-839
00829029200
008-018-454
009-513-213
00383951900
000147765000';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php