Python - 列出列表列表的理解

Question

我有一个列表列表,并希望生成一个列表列表,其中包含每个列表中的一个元素.

例如,给定列表[[1, 2], [3, 4], [5, 6], [7, 8],我将执行以下代码[(i, j, k, h) for i in [1, 2] for j in [3, 4] for k in [5, 6] for h in [7, 8]]并获取输出

[(1, 3, 5, 7), (1, 3, 5, 8), (1, 3, 6, 7), (1, 3, 6, 8), (1, 4, 5, 7), (1, 4, 5, 8), (1, 4, 6, 7), (1, 4, 6, 8), (2, 3, 5, 7), (2, 3, 5, 8), (2, 3, 6, 7), (2, 3, 6, 8), (2, 4, 5, 7), (2, 4, 5, 8), (2, 4, 6, 7), (2, 4, 6, 8)]

此代码不适用于具有不同数量的子列表的列表列表.有没有办法使用嵌套列表推导来实现所需的结果？(我的子列表并不总是相同的长度).

Answer 1

使用itertools.product,并在传递为参数时解压缩列表:

In [40]: from itertools import product

In [41]: list(product(*[[1, 2], [3, 4], [5, 6], [7, 8]]))
Out[41]: 
[(1, 3, 5, 7),
 (1, 3, 5, 8),
 (1, 3, 6, 7),
 (1, 3, 6, 8),
 (1, 4, 5, 7),
 (1, 4, 5, 8),
 (1, 4, 6, 7),
 (1, 4, 6, 8),
 (2, 3, 5, 7),
 (2, 3, 5, 8),
 (2, 3, 6, 7),
 (2, 3, 6, 8),
 (2, 4, 5, 7),
 (2, 4, 5, 8),
 (2, 4, 6, 7),
 (2, 4, 6, 8)]