Multiply Lists of strings in Python but not by scalar

Question

I would like to multiply 2 lists of strings in python but not by values. Like this example :

elem1 = ['a', 'b']
elem2 = ['c', 'd']
final = magic_function(elem1, elem2)
>> final = [
    ['a','c'],
    ['a','d'],
    ['b','c'],
    ['b','d']
]

I tried looking at the numpy package but I can't find anything which is not multiply by scalar

Possible duplicate of [Get the cartesian product of a series of lists?](https://stackoverflow.com/questions/533905/get-the-cartesian-product-of-a-series-of-lists) — Josh Lee, Sep 16 '17 at 18:24
Yup, I have edited the typo. I will look at all your solutions tomorrow, thanks for the answers guys ! — Benjamin Creusot, Sep 16 '17 at 22:26

score 1 · Answer 1 · answered Sep 16 '17 at 18:14

1

This can be done with a simple list comprehension final = [[v1, v2] for v1 in elem1 for v2 in elem2].

answered Sep 16 '17 at 18:14

Jonesinator

score 1 · Answer 2 · answered Sep 16 '17 at 18:48

1

import itertools
list(itertools.product(elem1,elem2))

By using itertools you can have the all possible combination of two lists. But it will generate list of tuples.

answered Sep 16 '17 at 18:48

P.Madhukar

bhansa · Answer 3 · 2017-09-16T18:56:57.193

0

Assuming

elem1 = ['a', 'b']
elem2 = ['c', 'd']

Using list comprehension:

[(a, b) for a in elem1 for b in elem2]

Result: [[('a', 'c'), ('b', 'd')], [('a', 'd'), ('b', 'c')]]

edited Sep 16 '17 at 18:56

answered Sep 16 '17 at 18:42

bhansa

OP's example doesn't look like permutations at all. – Eric Duminil Sep 16 '17 at 18:54

3 Answers3