python - 将多索引数据帧拆分为 pandas 中的平面数据帧

Question

我在 pandas 中有一个名为 groupt3 的多索引 df，当我输入 groupt3.head() 时它看起来像这样:

                datetime     song   sum   rat
artist datetime
2562     8      2            2      26    0
         46     19           19     26    0
         47     3            3      26    0
4Hero    1      2            2      32    0
         26     20           20     32    0
         9      10           10     32    0

我想要一个“平面”数据框，它采用艺术家索引和日期时间索引并“重复”以形成:

artist     date time    song   sum   rat
2562       8            2      26    0
2562       46           19     26    0
2562       47           3      26    0

等...

谢谢。

Answer 1

使用 pandas.DataFrame.to_records() .

例子:

import pandas as pd
import numpy as np
arrays = [['Monday','Monday','Tursday','Tursday'],
                        ['Morning','Noon','Morning','Evening']]
tuples = list(zip(*arrays))
index = pd.MultiIndex.from_tuples(tuples, names=['Weekday', 'Time'])
df = pd.DataFrame(np.random.randint(5, size=(4,2)), index=index)

In [39]: df
Out[39]: 
                 0  1
Weekday Time         
Monday  Morning  1  3
        Noon     2  1
Tursday Morning  3  3
        Evening  1  2

In [40]: pd.DataFrame(df.to_records())
Out[40]: 
   Weekday     Time  0  1
0   Monday  Morning  1  3
1   Monday     Noon  2  1
2  Tursday  Morning  3  3
3  Tursday  Evening  1  2