$re = '/\G\[(?:(?:name:(?<name>[^,\]]+)|quantity:(?<quantity>[^,\]]+)|unit_price:(?<unit_price>[^,\]]+)),?)*\](?:,|\z)/i';
$str = '[name:pizza,quantity:12,unit_price:3.43],[name:burger,unit_price:40.47,quantity:24],[quantity:4,unit_price:14.47,name:hotdog]';
preg_match_all($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