Read Only First Column of pandas DataFrame in CSV File in Python (Example)

 

In this Python tutorial you’ll learn how to import only the first column of a CSV file.

Table of contents:

Here’s the step-by-step process:

 

Example Data & Add-On Libraries

We first have to import the pandas library, in order to use the functions that are contained in the library:

import pandas as pd                       # Import pandas library

We’ll also have to create some data that we can use in the exemplifying syntax below:

data = pd.DataFrame({'x1':range(1, 9),    # Create pandas DataFrame
                     'x2':[7, 3, 1, 5, 3, 3, 9, 8],
                     'x3':[5, 2, 5, 1, 4, 1, 4, 7],
                     'x4':['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']})
print(data)                               # Print pandas DataFrame

 

table 1 DataFrame read only first column pandas dataframe csv file python

 

Have a look at the previous table. It shows that our example data consists of eight rows and four columns.

Let’s export these data to a CSV file:

data.to_csv('data.csv')                   # Export pandas DataFrame

At this point, you should find a new CSV file in your current working directory on your computer. We’ll use this CSV file for the example below.

Let’s continue!

 

Example: Read Only First Column from CSV File

The following syntax shows how to create a new pandas DataFrame from a CSV file that contains only the very first column of this file.

To achieve this, we have to set the usecols argument within the read_csv function to be equal to [1].

Consider the Python code below:

data_import = pd.read_csv('data.csv',     # Read first pandas DataFrame column
                           usecols = [1])
print(data_import)                        # Print imported pandas DataFrame

 

table 2 DataFrame read only first column pandas dataframe csv file python

 

In Table 2 you can see that we have created a new pandas DataFrame containing only the first column of our CSV file with the previous code.

 

Video & Further Resources

In case you need more information on the Python codes of this post, you might want to have a look at the following video on my YouTube channel. In the video, I illustrate the Python programming code of this tutorial in Python.

 

The YouTube video will be added soon.

 

Furthermore, you could have a look at some of the related posts on my homepage. A selection of articles is listed here.

 

Summary: In this tutorial you have learned how to read only the first column of a CSV file as a new pandas DataFrame in Python. Don’t hesitate to let me know in the comments section, in case you have additional comments or questions.

 

Subscribe to the Statistics Globe Newsletter

Get regular updates on the latest tutorials, offers & news at Statistics Globe.
I hate spam & you may opt out anytime: Privacy Policy.


Leave a Reply

Your email address will not be published.

Fill out this field
Fill out this field
Please enter a valid email address.

Menu
Top