Note: I'm using Python 3.
I have a list of sets of varying length, e.g.:
list_1 = [{(3, 4), (3, 1), (3, 3), (3, 2), (3, 5)}, {(9, 10), (9, 7), (9, 8), (9, 9)}, {(2, 9), (3, 9), (1, 9)}, {(6, 2), (5, 2)}, {(8, 3)}]
I want to find each tuple pair permutation, except where the pair is of two tuples in the same set. For example, (3,4)(9,10) and (3,1)(9,10) would be acceptable, but I do not want to output the pairs (3,4)(3,1) or (6,2)(5,2). How do I achieve this?
For some background, each set represents contiguous coordinates on a 10*10 grid. I want to find if any cell in one set is near any cell in another set, but I do not want cells in one set to check if they are near cells in their own set.
I tried to implement the following:
list_2 = itertools.permutations(list_1,2)
but this gives ALL permutations (as expected). Can I somehow implement the filter() function or something similar?
You can first permute the sets and then apply itertools.product to get the pairs from the sets.
from itertools import permutations, product
list_1 = [{(3, 4), (3, 1), (3, 3), (3, 2), (3, 5)}, {(9, 10), (9, 7), (9, 8), (9, 9)}, {(2, 9), (3, 9), (1, 9)}, {(6, 2), (5, 2)}, {(8, 3)}]
pairs = [pair for ss in permutations(list_1, r=2) for pair in product(*ss)]
print(pairs) # [((3, 3), (9, 10)), ((3, 3), (9, 7)), ((3, 3), (9, 8)), ...