Check if two variables have values from two different sets, the DRY way

Question

I have a range of values (L,R,U,D) and two variables, d and newd, containing one of them. I need to check if d and newd are in the same subset (L,R or U,D) or not.
I know I can do this:

d in {'L','R'} and newd in {'U','D'} or d in {'U','D'} and newd in {'L','R'}

this indeed returns False if they both have values in L,R or U,D, and True otherwise. Still, I find it much reduntant. Some suggestions about a more DRY approach?

Answer 1

If you know that there are only two sets and that your values must be in one or the other, then you can simplify it to this:

(d in set1) == (newd in set2)

Explanation:

• If d is in set 1 and newd is in set 2, both sides of the == are True, so the expression returns True.
• If d is in set 2 and newd is in set 1, both sides of the == are False, so the expression returns True.
• If they are in the same set, one side of the == will return False and the other True so the result of the expression will be False.