在单个cookie中存储和更新多个值

How can I store multiple values in a single cookie and keep adding more values in the same cookie.

For example:

If a user_id 1 votes a post_id 1, i want to store (1, 1) in the cookie.

If the user_id 1 votes a post_id 2, I want to update the same cookie with values (1,2).

Thanks.

use json to store array in single cookie

set cookie:

setcookie("myCookie", json_encode(array(1, 2)));

get cookie:

print_r(json_encode($_COOKIE["myCookie"]));