Python中list的元素出现频率
Intro
两种方法统计list中的元素出现次数。
Example 1
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>>> a = [1,1,1,1,2,2,2,2,3,3,4,5,5]
>>> d = {x:a.count(x) for x in a}
>>> d
{1: 4, 2: 4, 3: 2, 4: 1, 5: 2}
>>> a, b = d.keys(), d.values()
>>> a
dict_keys([1, 2, 3, 4, 5])
>>> b
dict_values([4, 4, 2, 1, 2])
Example 2(In Python 2.7+)
>>> import collections
>>> a = [1,1,1,1,2,2,2,2,3,3,4,5,5]
>>> counter=collections.Counter(a)
>>> d = collections.Counter(a)
>>> d
Counter({1: 4, 2: 4, 3: 2, 5: 2, 4: 1})
>>> a, b = d.keys(), d.values()
>>> a
dict_keys([1, 2, 3, 4, 5])
>>> b
dict_values([4, 4, 2, 1, 2])