Permutations between two lists

python list algorithm itertools combinatorics
user1735075 picture user1735075 · Oct 17, 2012 · Viewed 196k times · Source

I’m having trouble wrapping my head around a algorithm I’m try to implement. I have two lists and want to take particular combinations from the two lists.

Here’s an example.

names = 'a', 'b'
numbers = 1, 2

the output in this case would be:

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

I might have more names than numbers, i.e. len(names) >= len(numbers). Here's an example with 3 names and 2 numbers:

names = 'a', 'b', 'c'
numbers = 1, 2

output:

[('a', 1), ('b', 2)]
[('b', 1), ('a', 2)]
[('a', 1), ('c', 2)]
[('c', 1), ('a', 2)]
[('b', 1), ('c', 2)]
[('c', 1), ('b', 2)]

Answer

DrIDK picture DrIDK · Dec 2, 2015

The simplest way is to use itertools.product:

a = ["foo", "melon"]
b = [True, False]
c = list(itertools.product(a, b))
>> [("foo", True), ("foo", False), ("melon", True), ("melon", False)]

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