PHP - toggle state

The problem is simple, but I'm looking for a creative solution. We meet very often arrays, objects that has a property that can be toggled (it can be active or inactive, 1 or 0). What I want is a creative solution (a function) to transform 0 to 1, and 1 to 0. Some examples: ``` // First if ($state == 1) { $state = 0; } else { $state = 1; } // Second $states = array(1, 0); $state = $states[$state]; // Third $state = ($state == 1) ? 0 : 1; ``` Is there another, one line solution for this? Thanks, and enjoy the brainstorming.