Set Index of pandas DataFrame in Python (Example)

In this Python programming article you’ll learn how to add a column of a pandas DataFrame as an index.

Table of contents:

Let’s take a look at some Python codes in action.

Example Data & Libraries

If we want to use the functions of the pandas library, we first have to load pandas to Python:

import pandas as pd                         # Load pandas library

The following data is used as a basis for this Python tutorial:

data = pd.DataFrame({'x1':range(10, 15),    # Create pandas DataFrame
                     'x2':['a', 'b', 'c', 'd', 'e'],
                     'x3':range(10, 5, - 1)})
print(data)                                 # Print pandas DataFrame

Table 1 shows that our exemplifying data contains five rows and three columns. The index ranges from the value 0 to the number of rows in our data set.

Example: Set Column as pandas DataFrame Index Using set_index() Function

In this example, I’ll illustrate how to use a column of a pandas DataFrame as an index in Python.

To achieve this, we have to apply the set_index function as shown below:

data_new = data.set_index('x2')             # Apply set_index function
print(data_new)                             # Print updated DataFrame

The output of the previous Python programming syntax is shown in Table 2 – A new pandas DataFrame where the column x2 has been added as the index.

Video & Further Resources

If you need further information on the Python code of this tutorial, I recommend having a look at the following video on my YouTube channel. I illustrate the Python code of the present tutorial in the video.

Besides that, you may want to have a look at the related tutorials on my website:

• Get Max & Min Value of Column & Index in pandas DataFrame in Python
• Convert Index to Column of pandas DataFrame in Python
• Select Rows of pandas DataFrame by Index in Python
• Rename Index of pandas DataFrame in Python in R
• Get Index of Column in pandas DataFrame in Python
• pandas Library Tutorial in Python
• Introduction to Python Programming

You have learned in this tutorial how to use and add a column of a pandas DataFrame as an index in the Python programming language. Please let me know in the comments section, in case you have any further questions.