Python: Counting repeating values of a dictionary

问题

I have a dictionary as follows:

dictA = { ('unit1','test1') : 'alpha' , ('unit1','test2') : 'beta', ('unit2','test1') : 'alpha', ('unit2','test2') : 'gamma' , ('unit3','test1') : 'delta' , ('unit3','test2') : 'gamma'   }

How can I count the number of repeating values per each test independent of units?

i.e.

in 'test1' there is 2x 'alpha', 1x 'delta'

in 'test2' there is 1x 'beta', 2x 'gamma'

Any inputs?

Many Thanks.

回答1:

In Python 2.7 or 3.1 or above, you can use collections.Counter:

from collections import Counter
counts = Counter((k[1], v) for k, v in dictA.iteritems())
print(counts)

prints

Counter({('test1', 'alpha'): 2, ('test2', 'gamma'): 2, ('test2', 'beta'): 1, ('test1', 'delta'): 1})

来源：https://stackoverflow.com/questions/5490078/python-counting-repeating-values-of-a-dictionary