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

Its worth noting - and I only found this out after nearly 9 years of PHP coding that the best way of checking any variable exists is using the empty() function. This is because it doesn't generate errors and even though you turn them off - PHP still generates them! empty() however won't return errors if the variable doesn't exist. So I believe the correct answer is not to check if its null but to do the following

if (!empty($var) && is_null($var))

Note the PHP manual

variable is considered empty if it does not exist or if its value equals FALSE

As opposed to being null which is handy here!