获取键/值对的所有组合在Python字典

Question

这可能是一个愚蠢的问题，但考虑到以下字典：

combination_dict = {"one": [1, 2, 3], "two": [2, 3, 4], "three": [3, 4, 5]} 

我将如何实现这一目标列表：

result_list = [{"one": [1, 2, 3], "two": [2, 3, 4]}, {"one": [1, 2, 3], "three": [3, 4, 5]}, {"two": [2, 3, 4], "three": [3, 4, 5]}] 

在其他单词，我想要一个字典中的两个键/值对的所有组合，无需替换，无论顺序如何。

Answer 1

一种解决方案是使用itertools.combinations()：

result_list = map(dict, itertools.combinations(
    combination_dict.iteritems(), 2)) 

编辑：由于popular demand，这里一个Python 3.x版：

result_list = list(map(dict, itertools.combinations(
    combination_dict.items(), 2))) 

Answer 2

我通过@JollyJumper喜欢的解决方案可读性虽然这一个执行更快

>>> from itertools import combinations 
>>> d = {"one": [1, 2, 3], "two": [2, 3, 4], "three": [3, 4, 5]} 
>>> [{j: d[j] for j in i} for i in combinations(d, 2)] 
[{'three': [3, 4, 5], 'two': [2, 3, 4]}, {'three': [3, 4, 5], 'one': [1, 2, 3]}, {'two': [2, 3, 4], 'one': [1, 2, 3]}] 

个

时序：

>python -m timeit -s "d = {'three': [3, 4, 5], 'two': [2, 3, 4], 'one': [1, 2, 3]}; from itertools import combinations" "map(dict, combinations(d.iteritems(), 2))" 
100000 loops, best of 3: 3.27 usec per loop 

>python -m timeit -s "d = {'three': [3, 4, 5], 'two': [2, 3, 4], 'one': [1, 2, 3]}; from itertools import combinations" "[{j: d[j] for j in i} for i in combinations(d, 2)]" 
1000000 loops, best of 3: 1.92 usec per loop 

Answer 3

from itertools import combinations 
combination_dict = {"one": [1, 2, 3], "two": [2, 3, 4], "three": [3, 4, 5]} 
lis=[] 
for i in range(1,len(combination_dict)): 
    for x in combinations(combination_dict,i): 
     dic={z:combination_dict[z] for z in x} 
     lis.append(dic) 
print lis    

输出：

[{'three': [3, 4, 5]}, {'two': [2, 3, 4]}, {'one': [1, 2, 3]}, {'three': [3, 4, 5], 'two': [2, 3, 4]}, {'three': [3, 4, 5], 'one': [1, 2, 3]}, {'two': [2, 3, 4], 'one': [1, 2, 3]}] 

Answer 4

我相信这会得到你所需要的。

result list = [{combination_dict['one','two'],combination_dict['one','three']}] 

我发现这个教程是非常有益的：

http://bdhacker.wordpress.com/2010/02/27/python-tutorial-dictionaries-key-value-pair-maps-basics/