在 Python 中打印两个列表的组合

Question

我要打印的内容如下，为简单起见，在每个字符串中使用 2 个变量。我认为使用循环有问题，我对 Python 有点陌生。提前致谢！com0 <-(a) with (1,)com1 <-(a) with (2,)com2 <-(a) with (1, 2)com3 <-(b) with (1,)com4 <-(b) with (2,)com5 <-(b) with (1, 2)com6 <-(a,b) with (1,)com7 <-(a,b) with (2,)com8 <-(a,b) with (1, 2)这是我试过的：import itertoolsi = 0 #v1j = 0 #v2v1 = [1, 2]v2 = ["a","b"]while j < 2**len(v2):    for K in range(0, len(v2)+1):        while i < 2**len(v1):            for L in range(0, len(v1)+1):                for subset2 in itertools.combinations(v1, L):                    for subset1 in itertools.combinations(v2, K):                        print("com{0} <-{1} with {2}".format(i,subset1,subset2))                        i+=1                        j+=1

Answer 1

你不需要这么多循环。只需使用combinations并product从itertoools

>>> from itertools import combinations, product

>>> 

>>> v1 = [1, 2]

>>> v2 = ["a","b"]

>>> 

>>> all_v1 = [e for i in range(len(v1)) for e in combinations(v1,i+1)]

>>> all_v2 = [e for i in range(len(v1)) for e in combinations(v2,i+1)]

>>> 

>>> for i, (x,y) in enumerate(product(all_v2, all_v1)):

...     print (f'com{i} <-{x} with {y}')

... 

com0 <-('a',) with (1,)

com1 <-('a',) with (2,)

com2 <-('a',) with (1, 2)

com3 <-('b',) with (1,)

com4 <-('b',) with (2,)

com5 <-('b',) with (1, 2)

com6 <-('a', 'b') with (1,)

com7 <-('a', 'b') with (2,)

com8 <-('a', 'b') with (1, 2)

Answer 2

来自 itertools 的结果product()是两个列表的笛卡尔积。通过使用此函数，您可以避免所有循环：

import itertools

v1 = [1, 2]

v2 = ["a","b"]

combinations = list(itertools.product(v1, v2))

>> [(1, "a"), (1, "b"), (2, "a"), (2, "b")]