set_index()

Let’s read the budget.xlsx file into a DataFrame:

import pandas as pd

budget = pd.read_excel("budget.xlsx")

budget

Output:

Let’s say we want the Store Code column to serve as the index of our DataFrame. We can achieve this using the set_index() method:

budget.set_index(keys="Store Code", inplace=True)

budget

Output:

As we can see above, the Store Code column is no longer a regular column in our DataFrame - it has become the new index.

reset_index()

There is a complementary method called reset_index(), which moves the current index back into a column position and creates a brand new numeric pandas index.

budget.reset_index()

Output: