检查$ _COOKIE值是否为空

Question

I assign a cookie to a variable:

$user_cookie = $_COOKIE["user"];

How can I check if the $user_cookie received some value or not?

Should I use if (empty($user_cookie)) or something else?

Answer 1

Use isset() like so:

if (isset($_COOKIE["user"])){
$user_cookie = $_COOKIE["user"];
}

This tells you whether a key named user is present in $_COOKIE. The value itself could be "", 0, NULL etc. Depending on the context, some of these values (e.g. 0) could be valid.

PS: For the second part, I'd use === operator to check for false, NULL, 0, "", or may be (string) $user_cookie !== "".