如何计算 Python 中的组合

Question

I want to calculate a combination set as a collection of all possible subsets of k items selected from n items. For example, if n = 4 and k = 3 , then the items are the integers (0, 1, 2, 3) , then there are 4 possible combination elements:

[0, 1, 2]
[0, 1, 3]
[0, 2, 3]
[1, 2, 3]

Is there a function to do it in Python?

Answer 1

itertools.combinations produces the desired output:

from itertools import combinations

n = 4
k = 3

# combinations() outputs tuples.
# Use list() to transform the tuples into lists.
print([list(combination) for combination in combinations(range(n), 3)])