Create a random order of (x, y) pairs, without repeating/subsequent x's

Question

Say I have a list of valid X = [1, 2, 3, 4, 5] and a list of valid Y = [1, 2, 3, 4, 5].

I need to generate all combinations of every element in

Answer 1

This should do what you want.

rando will never generate the same X twice in a row, but I realized that it is possible (though seems unlikely, in that I never noticed it happen in the 10 or so times I ran without the extra check) that due to the potential discard of duplicate pairs it could happen upon a previous X. Oh! But I think I figured it out... will update my answer in a moment.

import random

X = [1,2,3,4,5]
Y = [1,2,3,4,5]


def rando(choice_one, choice_two):
    last_x = random.choice(choice_one)
    while True:
        yield last_x, random.choice(choice_two)
        possible_x = choice_one[:]
        possible_x.remove(last_x)
        last_x = random.choice(possible_x)


all_pairs = set(itertools.product(X, Y))
result = []
r = rando(X, Y)
while set(result) != all_pairs:
    pair = next(r)
    if pair not in result:
        if result and result[-1][0] == pair[0]:
            continue
        result.append(pair)

import pprint
pprint.pprint(result)