$re = '/^1?\(\d{3}\)[-. ]?(\d{3})$/m';
$str = '1(123)123
(123)123
1(123) 123
2(123) 123
1(123)%123
1(123)12
1(12)123';
preg_match_all($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