Get all pairwise combinations from a list
combinatorics, list, python
Solution
Though the previous answer will give you all pairwise orderings, the example expected result seems to imply that you want all unordered pairs.
This can be done with `itertools.combinations`:
>>> import itertools
>>> x = [1,2,3,4]
>>> list(itertools.combinations(x, 2))
[(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
Compare to the other result:
>>> list(itertools.permutations(x, 2))
[(1, 2), (1, 3), (1, 4), (2, 1), (2, 3), (2, 4), (3, 1), (3, 2), (3, 4), (4, 1), (4, 2), (4, 3)]
Problem
For example, if the input list is ``` [1, 2, 3, 4] ``` I want the output to be ``` [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)] ``` If possible, I would like a solution which is better than the brute force method of using two for loops. How do I implement this?