创建组合

Question

我想创建数字列表有三个值，并想覆盖从0每一个组合的名单 - 3。例如：

0, 0, 0 
0, 0, 1 
... 
1, 0, 3 
1, 1, 3 

一路3, 3, 3。

有没有比使用多个for循环更好的方法吗？

这里是我使用的代码：

for i in range (0, 4): 
    for x in range (0, 4): 
     for t in range (0, 4): 
     assign = [i, x, t] 

Answer 1

通常itertools.product：

list(itertools.product(range(4), repeat=3))

Answer 2

您可以使用itertools.product：

>>> from itertools import product 
>>> list(product({0, 1, 2, 3}, repeat=3)) 
[(0, 0, 0), (0, 0, 1), (0, 0, 2), (0, 0, 3), (0, 1, 0), (0, 1, 1), (0, 1, 2), (0, 1, 3), (0, 2, 0), (0, 2, 1), (0, 2, 2), (0, 2, 3), (0, 3, 0), (0, 3, 1), (0, 3, 2), (0, 3, 3), (1, 0, 0), (1, 0, 1), (1, 0, 2), (1, 0, 3), (1, 1, 0), (1, 1, 1), (1, 1, 2), (1, 1, 3), (1, 2, 0), (1, 2, 1), (1, 2, 2), (1, 2, 3), (1, 3, 0), (1, 3, 1), (1, 3, 2), (1, 3, 3), (2, 0, 0), (2, 0, 1), (2, 0, 2), (2, 0, 3), (2, 1, 0), (2, 1, 1), (2, 1, 2), (2, 1, 3), (2, 2, 0), (2, 2, 1), (2, 2, 2), (2, 2, 3), (2, 3, 0), (2, 3, 1), (2, 3, 2), (2, 3, 3), (3, 0, 0), (3, 0, 1), (3, 0, 2), (3, 0, 3), (3, 1, 0), (3, 1, 1), (3, 1, 2), (3, 1, 3), (3, 2, 0), (3, 2, 1), (3, 2, 2), (3, 2, 3), (3, 3, 0), (3, 3, 1), (3, 3, 2), (3, 3, 3)] 
>>> 

Answer 3

可以使用itertools.product()功能那个：

from itertools import product 

for i, x, t in product(range(4), repeat=3): 
    print (i, x, t) 

演示：

>>> from itertools import product 
>>> for i, x, t in product(range(4), repeat=3): 
...  print (i, x, t) 
... 
(0, 0, 0) 
(0, 0, 1) 
(0, 0, 2) 
(0, 0, 3) 
(0, 1, 0) 
# ... truncated for readability ... 
(3, 2, 3) 
(3, 3, 0) 
(3, 3, 1) 
(3, 3, 2) 
(3, 3, 3) 

Answer 4

的itertools.product()是一个很好的解决方案，但如果你万一要列表，而不是一个元组列表，你可以这样做：

[ [x,y,z] for x,y,z in itertools.product(range(4), repeat=3)] 

或相当的列表理解：

[ [x,y,z] for x in range(0,4) 
      for y in range(0,4) 
       for z in range(0,4)]