How to Reset Index in a Pandas DataFrame?

In this article, we will discuss multiple ways to reset index in a pandas DataFrame.

Table of Contents

Preparing Dataset

To quickly get started, let’s create a sample dataframe to experiment. We’ll use the pandas library with some random data.

import pandas as pd
import numpy as np

# List of Tuples
employees= [('Shubham', 'Data Scientist', 'Tech',   5),
            ('Riti', 'Data Engineer', 'Tech' ,   7),
            ('Shanky', 'Program Manager', 'PMO' ,   2),
            ('Shreya', 'Graphic Designer', 'Design' ,   2),
            ('Aadi', 'Backend Developer', 'Tech', 11),
            ('Sim', 'Data Engineer', 'Tech', 4)]

# Create a DataFrame object from list of tuples
df = pd.DataFrame(employees,
                  columns=['Name', 'Designation', 'Team', 'Experience'],
                 index = [10, 123, 33, 40, 20, 11])
print(df)

Contents of the created dataframe are,

        Name        Designation    Team  Experience
10   Shubham     Data Scientist    Tech           5
123     Riti      Data Engineer    Tech           7
33    Shanky    Program Manager     PMO           2
40    Shreya   Graphic Designer  Design           2
20      Aadi  Backend Developer    Tech          11
11       Sim      Data Engineer    Tech           4

As observed, the index in the above DataFrame is all over the place. Let’s explore multiple ways to reset it.

Reset index of DataFrame using the index property

Every DataFrame has an index property that can be used to get/set the index of the DataFrame. Let’s understand by resetting the index of the above DataFrame.

# resetting the index 
df.index = range(len(df))

print (df)

Output

      Name        Designation    Team  Experience
0  Shubham     Data Scientist    Tech           5
1     Riti      Data Engineer    Tech           7
2   Shanky    Program Manager     PMO           2
3   Shreya   Graphic Designer  Design           2
4     Aadi  Backend Developer    Tech          11
5      Sim      Data Engineer    Tech           4

Here, we have set the DataFrame index as the range value (from 0 to DataFrame length). Therefore, our DataFrame now contains index values 0 to 5.

Reset index of DataFrame using reset_index() function

The most commonly used function to reset index values is the pandas.DataFrame.reset_index() function. It is the most simplest function without any complications. Let’s try to again reset the index of the original DataFrame.

# reset index by dropping the current index
df.reset_index(drop=True, inplace=True)

print (df)

Output

      Name        Designation    Team  Experience
0  Shubham     Data Scientist    Tech           5
1     Riti      Data Engineer    Tech           7
2   Shanky    Program Manager     PMO           2
3   Shreya   Graphic Designer  Design           2
4     Aadi  Backend Developer    Tech          11
5      Sim      Data Engineer    Tech           4

Here you go, we have reset the DataFrame indexes. The two arguments used in the reset_index function are –
1. drop (default: False) – True means the current index column will be dropped, if False, it will create another column name “index” containing the original index values
2. inplace (default: False) – True means to store the changes in the DataFrame, if False, it will just print the changes but will not store them in the original DataFrame.

Reset index of DataFrame using set_index() function

The DataFrame.set_index() is another function to set the index of the DataFrame. The advantage of using this function is that it allows you to simply set any column as the index as well. Let’s try to set the index with the “Name” column values of the above DataFrame.

# Set column "Name" as the index of DataFrame
df.set_index(['Name'], inplace=True)

print (df)

Output

               Designation    Team  Experience
Name                                          
Shubham     Data Scientist    Tech           5
Riti         Data Engineer    Tech           7
Shanky     Program Manager     PMO           2
Shreya    Graphic Designer  Design           2
Aadi     Backend Developer    Tech          11
Sim          Data Engineer    Tech           4

Here you go, we now have the “Name” column as the index.

Summary

In this article, we have discussed multiple ways to reset index in a pandas DataFrame. Thanks.