Large Loop Nest Design, Anyway To Improve Speed?

I want to loop through a list and check all the possible combinations in it. Currently, I'm using a series of nested for loops, and obviously I'm not ecstatic with the speed using

Solution 1:

It looks like you want to cover all combinations of one item picked from list1, then two each from list2 - list5. If correct, you can certainly make things more efficient:

from itertools import chain, combinations, product

for comb in product(combinations(list1, 1),
                    combinations(list2, 2),
                    combinations(list3, 2), ...):

Each comb will be in the form ((l1,), (l2, l2), (l3, l3), (l4, l4), (l5, l5)), but you can flatten this out using chain.from_iterable:

comb = list(chain.from_iterable(comb))

To get [l1, l2, l2, l3, l3, l4, l4, l5, l5].

For a neatness improvement if not actual efficiency, you can define the lists to use and how many items to pick from each up front:

lists = [(list1, 1), (list2, 2), (list3, 2), (list4, 2), (list5, 2)]

forcombinproduct(*(combinations(l, n) forl, n in lists)):