pandas 数据框如何合并列 [英] Pandas Data Frame how to merge columns

问题描述

我在图片中有一个熊猫数据框.我如何将其变成下表所示的表格. (演示是在excel中进行的，但我只想向您说明表的外观-这个问题与从excel导入和导出数据框无关)

I have a pandas dataframe like in the picture. How can I turn it into the table like below. (the demonstration is in excel but I just want to illustrate to you how the table look like- this question does not related to importing and exporting dataframe from/to excel)

谢谢您

推荐答案

这是不可能的.

pandas.DataFrame的基础对象是numpy数组，它们不会按照您建议的方式对数据进行分组.因此，不能将任意列显示为分组数据.

Underlying pandas.DataFrame objects are numpy arrays, which do not group data in the way you suggest. Therefore, an arbitrary column cannot be displayed as grouped data.

选项1

可以通过使用MultiIndex来部分复制所需的输出:

It is possible to partially replicate your desired output by using MultiIndex:

import pandas as pd

df = pd.DataFrame([['AAA', 8, 2, 'BBB'],
                   ['AAA', 9, 5, 'BBB'],
                   ['AAA', 10, 6, 'BBB']],
                  columns=['Name', 'Score1', 'Score2', 'PM'])

res = df.set_index(['Name', 'PM'])

结果:

          Score1  Score2
Name PM                 
AAA  BBB       8       2
     BBB       9       5
     BBB      10       6

选项2

或者您可以在3列上添加一个虚拟列和set_index:

Or you can add a dummy column and set_index on 3 columns:

df['dummy'] = 0
res = df.set_index(['Name', 'PM', 'dummy'])

结果:

                Score1  Score2
Name PM  dummy                
AAA  BBB 0           8       2
         0           9       5
         0          10       6

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