$re = '/^\d+(?:\.\d{0,2})?(?:,\s*\d+(?:\.\d{0,2})?)*,?$/m';
$str = '1.23
1
1,
1.2,4
1.23, 4
1.23, 4,
1, 2.34
1.
1,,
1.234';
preg_match_all($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