RNG; One variable must not be equal to another

[DavidRobinsons]

Using combinations() here is clever but wouldn't scale. What you want is "sampling without replacement" and the easiest way to do that would be with a numpy function which allows you to set replacement to False. Apparently Python's random module doesn't have this built-in, which is somewhat unfortunate.

If you don't mind adding a dependency, I'd use numpy. Otherwise the random number generation and set checking is probably what I would do. As a third option, you could consider using the built-in random.shuffle() one time and then popping (this would be less efficient than set-checking, but more efficient than combinations).

I am starting to think last night that the thing I want to happen is beyond me for now, and I am starting to give up. But thanks for suggesting me three options, I'll look to them.