CODEWITHSUNDEEP
python
suizokukan
suizokukan

Reputation: 1373

product of lists, not necessarily all the lists at the same time

I have three lists (L1, L2, L3), something like :

L1 = [1,2]
L2 = ['a','b']
L3 = ['A','B']

I want to compute the product of L1*L2*L3, id est,

itertools.product(L1,L2,L3) = [ [1,'a','A'], [1,'a','B'], ... ]

but I want to take or not in account some lists; hence,[1,], [ 1, 'a' ] would be a part of the result, like ['a',], ['a', 'B'] and so on.

Any idea to help me ? Thanks !

Upvotes: 0

Views: 63

Answers (1)

interjay
interjay

Reputation: 110069

Use the powerset function given in the itertools examples. powerset([L1,L2,L3]) will give you all subsets of the set of 3 lists. For each subset you can take the cartesian product, and then chain them all together.

>>> from itertools import chain, product
>>> result = chain.from_iterable(product(*lists) for lists in powerset([L1,L2,L3]))        
>>> list(result)

[(), (1,), (2,), ('a',), ('b',), ('A',), ('B',), (1, 'a'), (1, 'b'), (2, 'a'), 
(2, 'b'), (1, 'A'), (1, 'B'), (2, 'A'), (2, 'B'), ('a', 'A'), ('a', 'B'), 
('b', 'A'), ('b', 'B'), (1, 'a', 'A'), (1, 'a', 'B'), (1, 'b', 'A'), 
(1, 'b', 'B'), (2, 'a', 'A'), (2, 'a', 'B'), (2, 'b', 'A'), (2, 'b', 'B')]

Upvotes: 3

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