将数据框与重叠列合并

Question

我有以下DataFrames：

    stores = [['AA', 12, 'Red'], ['BB', 13, 'Red'], ['BB', 14, 'Red'], ['BB', 15, 'Red']]
    visits = [['BB', 13, 'Green'], ['BB', 14, 'Blue']]

    stores_df = pd.DataFrame(data=stores, columns=['retailer', 'store', 'color'])
    stores_df.set_index(['retailer', 'store'], inplace=True)

    visits_df = pd.DataFrame(data=visits, columns=['retailer', 'store', 'color'])
    visits_df.set_index(['retailer', 'store'], inplace=True)

                color
retailer store       
BB       13     Green
         14      Blue

               color
retailer store      
AA       12      Red
BB       13      Red
         14      Red
         15      Red

如何合并它们以获得以下结果：

               color
retailer store      
AA       12      Red
BB       13      Green
         14      Blue
         15      Red

Answer 1

您可以使用update：

In [41]: stores_df.update(visits_df)

In [42]: stores_df
Out[42]:
                color
retailer store
AA       12       Red
BB       13     Green
         14      Blue
         15       Red

Answer 2

您想使用combine_first

visits_df.combine_first(stores_df)