Groupby and append lists and strings

Question

I am trying to group-by the values in my \"value_1\" column. But my last column is made up of lists. When I try to group-by using my \"value_1\" column, the column made up o

Answer 1

You could groupby value_1 and aggregate the columns containing strings with the following function:

def str_cat(x):
    return x.str.cat(sep=', ')

And use GroupBy.sum to append the lists in the column list:

df.replace('',None).groupby('value_1').agg({'list':'sum', 'value_2': str_cat,
                                            'value_3': str_cat})

                        list                       value_2  \
value_1                                                              
american  [supermarket, connivence, state]  california, nyc, texas   
canadian             [coffee, sipermarket]          toronto, texas   

                    value_3  
value_1                                 
american  walmart, kmart, dunkinDonuts  
canadian         dunkinDonuts, walmart