$value) {            $rand = mt_rand(1, $probabilitySum);            if ($rand <= $value) {                $result = $key;            }else{                $probabilitySum -= $value;            }        }        return $result;    }    $data = array(        1 => 10,        2 => 30,        3 => 40,        4 => 90,        10 => 100    );    var_dump(probability($data));