df.reset_index()

df.reset_index(drop=False)

Resets the index of df to the default one.

Input:

drop : boolean, default False

If False, adds index as a column to the DataFrame. If True, doesn't add index as a column into the DataFrame.

Returns:

A new DataFrame with or without the column set as the index

Return Type:

DataFrame

---

pets = pets.set_index('ID')
pets

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

pets.reset_index()

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!

Note that when drop=True, the previous index will be dropped instead of becoming a new column in the DataFrame.

pets.reset_index(drop=True)

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