如何使用子元组从元组创建列表？

Posted 2021-04-09

我有两个名单a和b。然后我创建所有组合，采用a的所有两长度组合加上b各一个：

import itertools as it

a = [1,2,3,4]
b = [5,6]

for i in it.product(it.combinations(a, 2), b):
    print (i)

# output:
  ((1, 2), 5)
  ((1, 2), 6)
  ((1, 3), 5)
  ...

# expected output:
  [1, 2, 5]
  [1, 2, 6]
  [1, 3, 5]
  ...

如何在循环操作阶段将元组转换为列表？

答案

以下理解将起作用：

>>> [[*x, y] for x, y in it.product(it.combinations(a, 2), b)]  # Py3
>>> [list(x) + [y] for x, y in it.product(it.combinations(a, 2), b)]  # all Py versions
[[1, 2, 5],
 [1, 2, 6],
 [1, 3, 5],
 [1, 3, 6],
 [1, 4, 5],
 [1, 4, 6],
 [2, 3, 5],
 [2, 3, 6],
 [2, 4, 5],
 [2, 4, 6],
 [3, 4, 5],
 [3, 4, 6]]

另一答案

简化方法：

a = [1,2,3,4]
b = [5,6]
l = len(a)
print(sorted([a[i], a[i_n], j] for i in range(l) for j in b
             for i_n in range(i+1, l) if i < l-1))

输出：

[[1, 2, 5], [1, 2, 6], [1, 3, 5], [1, 3, 6], [1, 4, 5], [1, 4, 6], [2, 3, 5], [2, 3, 6], [2, 4, 5], [2, 4, 6], [3, 4, 5], [3, 4, 6]]