计算密钥的一部分出现在字典python中的次数

Question

我有以下字典,我想计算键出现的次数,字典是非常大的.

a = { (1,2):3, (1,3):5, (2,1):6 }

我想要这个结果

1: 3 times
2: 2 times
3: 1 time

Answer 1

使用itertools.chain和collections.Counter:

collections.Counter(itertools.chain(*a.keys()))

或者:

collections.Counter(itertools.chain.from_iterable(a.keys()))

Answer 2

>>> from collections import Counter
>>> a = { (1,2):3, (1,3):5, (2,1):6 }
>>> 
>>> Counter(j for k in a for j in k)
Counter({1: 3, 2: 2, 3: 1})