$re = '/^(?!0{3})\d{5}(?:-?\d{4})?$/m';
$str = '12345
12345-6789
123456789
00000
00000-0000
000000000
00000
00012-3214
00139
00136-3654
00336-69856
';
preg_match_all($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