pandas 数据框，如何获取某个索引值的平均值
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pandas dataframe, how to get average of a value over a certain index
提问by Albert X.W.
For example, I have a dataframe like this:
例如，我有一个这样的数据框：
Age Gender
20 Male
10 Male
18 Female
15 Male
19 Female
17 Female
How can I can a DataFrame like:
我怎样才能像 DataFrame 这样：
Age Gender
15 Male
18 Female
The age in the new DataFrame is the average age of the old DataFrame with corresponding Gender respectively.
新DataFrame中的age分别是对应Gender的旧DataFrame的平均年龄。
回答by MaxU
In [51]: df.groupby('Gender', as_index=False).Age.mean()
Out[51]:
Gender Age
0 Female 18
1 Male 15
How can I make the result DataFrame a Series with Gender as keys/index?
如何使结果 DataFrame 成为以 Gender 作为键/索引的系列？
In [61]: s = df.groupby('Gender').Age.mean()
In [62]: s
Out[62]:
Gender
Female 18
Male 15
Name: Age, dtype: int64
In [63]: type(s)
Out[63]: pandas.core.series.Series
