php group by SUM using multi dimensional array

Question

I have a php array like this:

 Array
    (
        [0] => Array
            (
                [url_id] => 2191238
                [time_spent] => 41         


        

Answer 1

Why not a simpler

$ts_by_url = array();
foreach($array as $data) {
    $ts_by_url[ $data['url_id'] ] += $data['time_spent'];
}