How to Reset an Index in Python?

To reset an index in Python, you can use the reset_index() method available in pandas, a popular data manipulation library. This method resets the index of a DataFrame or a Series, providing a new default numerical index.

Here’s an example of how to reset an index using the reset_index() method:

import pandas as pd

# Create a DataFrame
data = {'Name': ['John', 'Emma', 'Peter', 'Olivia'],
        'Age': [25, 28, 30, 27]}
df = pd.DataFrame(data)

# Set 'Name' column as the index
df.set_index('Name', inplace=True)

# Print the DataFrame with the modified index
print(df)

Output:

        Age
Name       
John     25
Emma     28
Peter    30
Olivia   27

The DataFrame df has the ‘Name’ column set as the index. To reset the index, you can call the reset_index() method:

# Reset the index
df_reset = df.reset_index()

# Print the DataFrame with the reset index
print(df_reset)

Output:

     Name  Age
0    John   25
1    Emma   28
2   Peter   30
3  Olivia   27

In the code above, the reset_index() method is called on the DataFrame df, and the result is assigned to a new DataFrame called df_reset. The new DataFrame df_reset has a default numerical index, and the original index becomes a regular column named ‘Name’.

Note that the reset_index() method does not modify the original DataFrame but returns a new DataFrame with the reset index. If you want to modify the DataFrame in-place, you can pass the inplace=True parameter to the reset_index() method like this: df.reset_index(inplace=True).