python - Pandas Dataframe Groupby 多列

Question

我有以下数据框:

FACTORY_ID  SUPPLIER_ID DELIVERY_DATETIME
A   1   05/09/2015 11:00
A   1   05/09/2015 11:00
A   2   05/09/2015 11:00
A   2   08/09/2015 11:00
A   1   08/09/2015 11:00
A   1   08/09/2015 11:00
A   1   08/09/2015 11:00
A   2   08/09/2015 11:00
A   2   13/09/2015 11:00
A   3   13/09/2015 11:00
A   3   13/09/2015 11:00
A   3   13/09/2015 11:00
A   3   13/09/2015 11:00
A   3   13/09/2015 11:00

我打算使用 GroupBy 子句对其进行转换，以显示用于演示的数据的汇总 View 。 (DELIVERY_DATETIME 是连接并以逗号分隔的列。)此示例中所需的结果:

FACTORY_ID  SUPPLIER_ID DELIVERY_DATETIME
A   1   05/09/2015  11:00:00 AM, 08/09/2015  11:00:00 AM
A   2   05/09/2015  11:00:00 AM, 13/09/2015  11:00:00 AM
A   3   13/09/2015  11:00:00 AM

尝试过 GroupBy/drop_duplicates 但无法得到我想要的。我应该怎样做呢？

Answer 1

IIUC groupby 和 agg

newdf=df.groupby(['FACTORY_ID','SUPPLIER_ID']).DELIVERY_DATETIME.agg(['first','last'])
newdf.loc[newdf['first']==newdf['last'],'last']=''
newdf
Out[69]: 
                             first        last
FACTORY_ID SUPPLIER_ID                        
A          1            05/09/2015  08/09/2015
           2            05/09/2015  13/09/2015
           3            13/09/2015