单个变量的频率表

问题描述

当天最后一个新手熊猫问题:如何为单个系列生成表格?

One last newbie pandas question for the day: How do I generate a table for a single Series?

例如:

my_series = pandas.Series([1,2,2,3,3,3])
pandas.magical_frequency_function( my_series )

>> {
     1 : 1,
     2 : 2,
     3 : 3
   }

很多谷歌搜索使我进入了Series.describe()和pandas.crosstabs，但是这些都不满足我的需要:一个变量，按类别计数.哦，如果它适用于不同的数据类型(字符串，整数等)，那就太好了.

Lots of googling has led me to Series.describe() and pandas.crosstabs, but neither of these does quite what I need: one variable, counts by categories. Oh, and it'd be nice if it worked for different data types: strings, ints, etc.

推荐答案

也许是.value_counts()?

>>> import pandas
>>> my_series = pandas.Series([1,2,2,3,3,3, "fred", 1.8, 1.8])
>>> my_series
0       1
1       2
2       2
3       3
4       3
5       3
6    fred
7     1.8
8     1.8
>>> counts = my_series.value_counts()
>>> counts
3       3
2       2
1.8     2
fred    1
1       1
>>> len(counts)
5
>>> sum(counts)
9
>>> counts["fred"]
1
>>> dict(counts)
{1.8: 2, 2: 2, 3: 3, 1: 1, 'fred': 1}

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