Панды суммируют несколько столбцов Groupby
df.groupby(['col1','col2']).agg({'col3':'sum','col4':'sum'}).reset_index()
Comfortable Cardinal
df.groupby(['col1','col2']).agg({'col3':'sum','col4':'sum'}).reset_index()
#UPDATED (June 2020): Introduced in Pandas 0.25.0,
#Pandas has added new groupby behavior “named aggregation” and tuples,
#for naming the output columns when applying multiple aggregation functions
#to specific columns.
df.groupby(
['col1','col2']
).agg(
sum_col3 = ('col3','sum'),
sum_col4 = ('col4','sum'),
).reset_index()