Optional parameters to PHP list function

Question

I have a line like this in my code:

list($user_id, $name, $limit, $remaining, $reset) = explode(\'|\', $user);

The last 3 parameters may or

Answer 1

list($user_id, $name, $limit, $remaining, $reset)
    = array_pad(explode('|', $user), 5, null);