$re = '/,(?=[^)]*(?:[(]|$))/';
$str = 'rttr,ertrret,ertret(yes,no),ete(,)ert,ert ert,rtrter,0
rttr,ert(yes,no)rret,ert ret,eteert,ertert,rtrter,1
rttr,ertrret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,eteert,ertert,rtrter,2
rttr,ert(white,black)rret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,et(blue,green,yellow,orange,white)eert,ertert,rtrter,1';
preg_match_all($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