sum()

df.groupby(column_name).sum()

Returns a DataFrame, with rows as groups, and each column as the sum of the column values within each group.

Note:: Only for columns of type int or float, all other columns are automatically dropped.

pets

Index	ID	Species	Color	Weight	Age	Is_Cat	Owner_Comment
0	dog_001	dog	black	40	5	False	There are no bad dogs, only bad owners.
1	cat_001	cat	golden	1.5	0.2	True	My best birthday present ever!!!
2	cat_002	cat	black	15	9	True	**All you need is love and a cat.**
3	dog_002	dog	white	80	2	False	Love is a wet nose and a wagging tail.
4	dog_003	dog	black	25	0.5	False	Be the person your dog thinks you are.
5	ham_001	hamster	black	1	3	False	No, thank you!
6	ham_002	hamster	golden	0.25	0.2	False	No, thank you!
7	cat_003	cat	black	10	0	True	No, thank you!

# Most cases, this won't be very helpful!
pets.groupby('Species').sum()

Index	ID	Color	Weight	Age	Is_Cat	Owner_Comment
cat	cat_001cat_002cat_003	goldenblackblack	26.5	9.2	3	My best birthday present ever!!!**All you need is love and a cat.**No, thank you!
dog	dog_001dog_002dog_003	blackwhiteblack	145	7.5	0	There are no bad dogs, only bad owners.Love is a wet nose and a wagging tail.Be the person your dog thinks you are.
hamster	ham_001ham_002	blackgolden	1.25	3.2	0	No, thank you!No, thank you!

pets.get(['Weight', 'Age', 'Species', 'Is_Cat']).groupby('Species').sum()

Index	Weight	Age	Is_Cat
cat	26.5	9.2	3
dog	145	7.5	0
hamster	1.25	3.2	0