python中两个列表的排列

Question

我有两个列表,如:

list1 = ['square','circle','triangle']
list2 = ['red','green']

如何创建这些列表的所有排列,如下所示:

[
  'squarered', 'squaregreen',
  'redsquare', 'greensquare',
  'circlered', 'circlegreen',
  'redcircle', 'greencircle',
  'trianglered', 'trianglegreen',
  'redtriangle', 'greentriangle'
]

我可以用itertools它吗？

Answer 1

你想要这个itertools.product方法,它会给你两个列表的笛卡尔积.

>>> import itertools
>>> a = ['foo', 'bar', 'baz']
>>> b = ['x', 'y', 'z', 'w']

>>> for r in itertools.product(a, b): print r[0] + r[1]
foox
fooy
fooz
foow
barx
bary
barz
barw
bazx
bazy
bazz
bazw

您的示例要求提供双向产品(即,您需要'xfoo'以及'foox').要做到这一点,只需做另一个产品并链接结果:

>>> for r in itertools.chain(itertools.product(a, b), itertools.product(b, a)):
...   print r[0] + r[1]

Answer 2

>>> import itertools
>>> map(''.join, itertools.chain(itertools.product(list1, list2), itertools.product(list2, list1)))
['squarered', 'squaregreen', 'circlered',
'circlegreen', 'trianglered', 'trianglegreen',
'redsquare', 'redcircle', 'redtriangle', 'greensquare',
'greencircle', 'greentriangle']

Answer 3

怎么样

[x + y for x in list1 for y in list2] + [y + x for x in list1 for y in list2]

IPython交互示例:

In [3]: list1 = ['square', 'circle', 'triangle']

In [4]: list2 = ['red', 'green']

In [5]: [x + y for x in list1 for y in list2] + [y + x for x in list1 for y in list2]
Out[5]: 
['squarered',
 'squaregreen',
 'circlered',
 'circlegreen',
 'trianglered',
 'trianglegreen',
 'redsquare',
 'greensquare',
 'redcircle',
 'greencircle',
 'redtriangle',
 'greentriangle']

Answer 4

我认为你要找的是两个列表的产物,而不是排列:

#!/usr/bin/env python
import itertools
list1=['square','circle','triangle'] 
list2=['red','green']
for shape,color in itertools.product(list1,list2):
    print(shape+color)

产量

squarered
squaregreen
circlered
circlegreen
trianglered
trianglegreen

如果你想既squarered和redsquare,那么你可以做这样的事情:

for pair in itertools.product(list1,list2):
    for a,b in itertools.permutations(pair,2):
        print(a+b)

或者,使其成为一个列表:

l=[a+b for pair in itertools.product(list1,list2)
   for a,b in itertools.permutations(pair,2)]
print(l)

产量

['squarered', 'redsquare', 'squaregreen', 'greensquare', 'circlered', 'redcircle', 'circlegreen', 'greencircle', 'trianglered', 'redtriangle', 'trianglegreen', 'greentriangle']

Answer 5

在任何情况下，您都可以执行以下操作：

perms = []
for shape in list1:
  for color in list2:
    perms.append(shape+color)