$re = '/^\s*((\d|[1-9]\d+)(\s+(\d|[1-9]\d+)){2}(\s+((0x(\d|[a-f]|[A-F}]){1,8})|[1-9]\d+|\d))*)\s*(,\s*(\d|[1-9]\d+)(\s+(\d|[1-9]\d+)){2}(\s+((0x(\d|[a-f]|[A-F}]){1,8})|[1-9]\d+|\d))*)*\s*$/';
$str = '1 1 1 1, 1 1 1 2, 1 01 1';
preg_match_all($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