check if variable empty

Question

if ($user_id == NULL || $user_name == NULL || $user_logged == NULL) {
    $user_id = \'-1\';
    $user_name = NULL;
    $user_logged = NULL;
}
if ($user_admin == NUL         


        

Answer 1

If you want to test whether a variable is really NULL, use the identity operator:

$user_id === NULL  // FALSE == NULL is true, FALSE === NULL is false
is_null($user_id)

If you want to check whether a variable is not set:

!isset($user_id)

Or if the variable is not empty, an empty string, zero, ..:

empty($user_id)

If you want to test whether a variable is not an empty string, ! will also be sufficient:

!$user_id