pandas 如何获取pandas MultiIndex数据框中的索引值?

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时间:2020-09-13 21:44:29  来源:igfitidea点击:

How to get the index value in pandas MultiIndex data frame?

pythonpandas

提问by colinfang

df = pd.DataFrame({'a':[2,3,5], 'b':[1,2,3], 'c':[12,13,14]})
df.set_index(['a','b'], inplace=True)
display(df)
s = df.iloc[1]
# How to get 'a' and 'b' value from s? 

It is so annoying that ones columns become indices we cannot simply use df['colname'] to fetch values.

令人讨厌的是,这些列变成了索引,我们不能简单地使用 df['colname'] 来获取值。

Does it encourage we use set_index(drop=False)?

它鼓励我们使用set_index(drop=False)吗?

回答by Wesley Bowman

When I print s I get

当我打印 s 我得到

In [8]: s = df.iloc[1]

In [9]: s
Out[9]:  
c    13
Name: (3, 2), dtype: int64

which has a and b in the name part, which you can access with:

其中名称部分有 a 和 b,您可以使用以下命令访问:

s.name

Something else that you can do is

你可以做的其他事情是

df.index.values

and specifically for your iloc[1]

并且专门针对您的 iloc[1]

df.index.values[1]

Does this help? Other than this I am not sure what you are looking for.

这有帮助吗?除此之外,我不确定您在寻找什么。

回答by ricmarchao

if you want to get "a" and "b"

如果你想得到“a”和“b”

df.index.names

df.index.names

gives: FrozenList(['a', 'b'])

给出:FrozenList(['a', 'b'])