$re = '/^([2-3]{1})([0-9]{2})(0[1-9]|1[012])(0[1-9]|[1-2][0-9]|3[0-1])(0[1-4]|[1-2][1-9]|3[1-5]|88)[0-9]{3}([0-9]{1})[0-9]{1}$/';
$str = '28311210102571';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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