How to properly configure Input to only return variables in $_GET, if any

[Chaosxmk]

I'm trying to get a list of variables in $_GET using:

$input = new Joomla\Input\Input;
$get = $input->get->getArray();

But when there isn't anything in $_GET, it returns everything. Is there something I can passthru getArray() that will limit it? I'm trying to avoid just using $_GET because I want consistent code, but if that's the only way, it's the only way.