Possible to merge rows in Pandas Dataframe and Concat defined fields

I am looking to combine rows in a DataFrame based on a grouping - but struggling to even get started with it.

For one field, I want to concatenate values. For another I want to sum.

Example:

• I want to group on col_a and col_d
• I want to concatenate col_b with a | separator
• I want to sum col_c

Input

col_a    col_b    col_c    col_d
Alex     Milk     5        UK
Alex     Sugar    4        USA
David    Rice     3        Spain
Alex     Wheat    1        UK

Output:

col_a    col_b          col_c    col_d
Alex     Milk | Wheat   6        UK
Alex     Sugar          4        USA
David    Rice           3        Spain

You can use groupby.agg()

out = df.groupby(['col_a', 'col_d'], as_index=False).agg(
    {
        'col_b': lambda x: ' | '.join(x),  
        'col_c': 'sum'                    
    }
)


print(out)

 col_a     col_d         col_b       col_c
0   Alex     UK       Milk | Wheat      6
1   Alex    USA           Sugar         4
2  David  Spain           Rice          3