$re = '/(?P<block>(?P<subject>[A-Z]{2,12})(?:(?P<operation>\*|\+)(?P<value>\d+(?:.?\d{1,2})?))?)/';
$str = 'JK+6.00,PP*2,ZZ,GROUPO';
preg_match_all($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