$re = '/(?:\d+(?:-\d+)?,?)+/m';
$str = '1,2,3,4-7,22-30,32,31 - valid
1,2,3,4-7,22-30,32,31,1-10 - invalid as some are overlapping with other
33,45,33-45,3345 - invalid';
preg_match_all($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