transform映射失败-报错 unique is not a valid function name for transfor

 1.当聚合字段是数值型时，用map(str)转化成字符串

df.groupby('Date').Data.transform(lambda x: ",".join(map(str, x.unique())))

2.当聚合字段是字符串类型

df['consol_info']=df.groupby('container_no')['lot_nr'].transform(lambda x:", ".join(x.unique()))
df['Countries_percontainer']=df.groupby('container_no')['Country'].transform(lambda x:", ".join(x.unique()))