count()

df.groupby(column_name).count()

Returns a DataFrame, with rows as groups, and all columns as the number of rows in each group.

Note:: All columns have the same value. It is advised to drop and rename the columns.

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!

pets.groupby('Species').count()

Index	ID	Color	Weight	Age	Is_Cat	Owner_Comment
cat	cat_003	golden	15	9	True	No, thank you!
dog	dog_003	white	80	5	False	Love is a wet nose and a wagging tail.
hamster	ham_002	golden	1	3	False	No, thank you!