统计列表列表中每个唯一项的出现次数

您可以使用: itertools.chain collections.Counter

In [94]: import itertools as it

In [95]: from collections import Counter

In [96]: Counter(it.chain(*map(set, listoflist)))
Out[96]: Counter({'A': 2, 'B': 2, 'C': 2, 'D': 2, 'X': 1, 'Y': 1, 'Z': 2})

如@Jean-Fran§ois Fabre评论中所述,您还可以使用:

In [97]: Counter(it.chain.from_iterable(map(set, listoflist)))
Out[97]: Counter({'A': 2, 'B': 2, 'C': 2, 'D': 2, 'X': 1, 'Y': 1, 'Z': 2})

本质上,你似乎想要

Counter(x for xs in listoflist for x in set(xs))

Counter .

from collections import Counter

listoflist = [["A", "B", "A", "C", "D"], ["Z", "A", "B", "C"], ["D", "D", "X", "Y", "Z"]]

c = Counter(x for xs in listoflist for x in set(xs))

print(c)

结果:

# output:
# Counter({'B': 2, 'C': 2, 'Z': 2, 'D': 2, 'A': 2, 'Y': 1, 'X': 1})

另一种方法是使用熊猫:

import pandas as pd

df = pd.DataFrame(listoflist)
df.stack().reset_index().groupby(0)['level_0'].nunique().to_dict()

输出:

{'A': 2, 'B': 2, 'C': 2, 'D': 2, 'X': 1, 'Y': 1, 'Z': 2}