python - 反转多个集合的字典

Question

假设我有一个集合字典:

DictofSets={
    'Key1':set(['A', 'B', 'D', 'F']),
    'Key2':set(['B', 'C', 'G']),
    'Key3':set(['A', 'B', 'D', 'F']),
    'Key4':set(['A', 'B', 'C', 'D', 'F']),
    'Key5':set(['A', 'B', 'E', 'F'])}

现在假设我想查找出现在多个集合中的集合元素的键。

我能做的最好的事情是:

from collections import Counter

# first get counts of elements in excess of 1:
c=Counter()
for s in DictofSets.values():
    c+=Counter(s)

# dict of lists for the keys if the set item occurs more than once
inverted={k:[] for k, v in c.items() if v>1} 
for k in sorted(DictofSets):
    for e in DictofSets[k]:
        if e in inverted:
            inverted[e].append(k)

它产生了我想要的东西:

>>> inverted
{'A': ['Key1', 'Key3', 'Key4', 'Key5'], 
 'C': ['Key2', 'Key4'], 
 'B': ['Key1', 'Key2', 'Key3', 'Key4', 'Key5'], 
 'D': ['Key1', 'Key3', 'Key4'], 
 'F': ['Key1', 'Key3', 'Key4', 'Key5']}

但是看起来有点笨拙。有没有更简单的方法来做到这一点？

Answer 1

我不认为OP的方法有什么问题。它可以更简洁地表达，但这并没有使它变得更好:

>>> import itertools as it
>>> c = Counter(it.chain.from_iterable(DictofSets.values()))
>>> {l: {k for k, s in DictofSets.items() if l in s} for l, n in c.items() if n > 1}
{'A': {'Key1', 'Key3', 'Key4', 'Key5'},
 'B': {'Key1', 'Key2', 'Key3', 'Key4', 'Key5'},
 'C': {'Key2', 'Key4'},
 'D': {'Key1', 'Key3', 'Key4'},
 'F': {'Key1', 'Key3', 'Key4', 'Key5'}}