两个字符串中的常见字母

用途

collections.Counter

>>> from collections import Counter>>> Counter('common')Counter({'m': 2, 'o': 2, 'c': 1, 'n': 1})>>> Counter('connor')Counter({'o': 2, 'n': 2, 'c': 1, 'r': 1})>>> common = Counter('common') & Counter('connor') # intersection>>> commonCounter({'o': 2, 'c': 1, 'n': 1})>>> sum(common.values())4