问题
For example,
list = [0, 1, 2]
I want a list of all possible 2-combinations:
combinations = [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2), (2,0), (2,1), (2,2)]
It seems to me that all the tools in itertools in Python only make one of (1,0) and (0,1), not both, I need both. Any suggestions, other than entering them by hand?
回答1:
You are looking for a Cartesian product of that list with itself, not a permutation nor a combination. Therefore you should use itertools.product with repeat=2:
from itertools import product
li = [0, 1, 2]
print(list(product(li, repeat=2)))
>> [(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]
回答2:
Can be done by importing itertools:
import itertools
list1 = [0, 1, 2]
print(list(itertools.product(list1,repeat=2)))
Output:
[(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]
Resource: You can learn more about it - here
来源：https://stackoverflow.com/questions/41088160/how-to-calculate-a-cartesian-product-of-a-list-with-itself