$re = '/^(1\s?\(\d{3}\)\s?|1\s\d{3}[\s-]?|\(\d{3}\)\s?|\d{3}[\s-]?)\d{3}[\s-]?\d{4}$/';
$str = '';
preg_match($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