How can I exclude admin(uid=1) for "Views Argument PHP Validator code" which limit a view to a User’s uid value?
That is a basic PHP problem, it does not concern Drupal so much. You want to admit access to the admin user always, so you will want to exclude that user's user id of any checks. However, your logic is wrong. The correct version would be

global $user;
return ($user-&gt;uid == 1 || $user-&gt;uid == $argument);


Which firstly returns true if the user is the admin user and secondly returns true if the user id matches the argument.