将 Multiindex DataFrame 的行组合成逗号分隔的列表

Question

给定一个多索引 DataFrame，我想组合重复的索引对并将它们的值列为逗号分隔列表。比如输入：

df = pd.DataFrame({'Last Name' : ['Deere','Deere','Foo'   ,'Foo'  ,'Man'   ],
                   'First Name': ['John' ,'Jane' ,'Kung'  ,'Kung' ,'Karate'],
                   'Value1':     [ 1     , 2     , 3      , 4     , 5      ],
                   'Value2':     ['Green','Blue' ,'Yellow','Black','Purple']})

df.set_index(['Last Name','First Name'],inplace=True)

提供：

                          Value1    Value2
Last Name   First Name      
Deere       John          1         Green
            Jane          2         Blue
Foo         Kung          3         Yellow
            Kung          4         Black
Man         Karate        5         Purple

我想将其转换为以下 DataFrame：

                          Value1    Value2
Last Name   First Name      
Deere       John          1         Green
            Jane          2         Blue
Foo         Kung          3,4       Yellow,Black
Man         Karate        5         Purple

Answer 1

您可以先通过 astype, then groupby by levels Last Name and First Name with agg join:

将列 Value1 转换为 string

df['Value1'] = df['Value1'].astype(str)
result = df.groupby(level=['Last Name','First Name'], sort=False).agg( ','.join)
print result
                     Value1        Value2
Last Name First Name                     
Deere     John            1         Green
          Jane            2          Blue
Foo       Kung          3,4  Yellow,Black
Man       Karate          5        Purple

将 Multiindex DataFrame 的行组合成逗号分隔的列表

Combine Rows of Multiindex DataFrame into Comma Separated Lists

python

pandas

dataframe

multi-index