How To Add Col To Csv With Panda

Add New Column to Existing CSV File in Python (Example)

In this tutorial y'all'll larn how to add a new column to a CSV file in the Python programming language.

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Let's become started!

Example Data & Add together-On Libraries

We offset accept to load the pandas library, in club to apply the corresponding functions:

                import                pandas                as                pd                # Import pandas library

import pandas as pd # Import pandas library

Furthermore, take a look at the exemplifying pandas DataFrame beneath:

data                =                pd.DataFrame                (                {                'x1':range                (                10                ,                17                )                ,                # Create pandas DataFrame                'x2':[                'a'                ,                'b'                ,                'c'                ,                'd'                ,                'due east'                ,                'f'                ,                'thousand'                ]                ,                'x3':[                3                ,                9                ,                vii                ,                7                ,                3                ,                2                ,                five                ]                ,                'x4':range                (                15                ,                8                ,                -                1                )                }                )                print                (data)                # Print pandas DataFrame

information = pd.DataFrame({'x1':range(10, 17), # Create pandas DataFrame 'x2':['a', 'b', 'c', 'd', 'e', 'f', 'g'], 'x3':[iii, ix, 7, 7, 3, 2, 5], 'x4':range(15, 8, - 1)}) impress(data) # Print pandas DataFrame

table 1 DataFrame add new column existing csv file python

Have a look at the previous table. It shows that our case information contains seven rows and four columns.

Let's export this data fix to a CSV file that we can use for the post-obit example:

data.to_csv                (                'data.csv'                ,                alphabetize                =                False                )                # Consign pandas DataFrame

data.to_csv('data.csv', index = False) # Export pandas DataFrame

Furthermore, consider the following list object. In the following example, we volition add together this list every bit a new column to our pandas DataFrame:

new_col                =                [                'foo'                ,                'bar'                ,                'foo'                ,                'foo'                ,                'bar'                ,                'bar'                ,                'bar'                ]                # Create list object                print                (new_col)                # Print list object                # ['foo', 'bar', 'foo', 'foo', 'bar', 'bar', 'bar']

new_col = ['foo', 'bar', 'foo', 'foo', 'bar', 'bar', 'bar'] # Create list object impress(new_col) # Print list object # ['foo', 'bar', 'foo', 'foo', 'bar', 'bar', 'bar']

Now, we are gear up up and can motility on to the instance lawmaking…

Example: Appending a New Cavalcade to a pandas DataFrame in a CSV File

In this example, I'll illustrate how to append a new variable to a pandas DataFrame in a CSV file in Python.

For this task, we first accept to import the CSV file using the read_csv function:

data_new                =                pd.read_csv                (                'data.csv'                )                # Read CSV file

data_new = pd.read_csv('data.csv') # Read CSV file

In the next step, we can add together our list equally a new column to our pandas DataFrame:

data_new[                'new_col'                ]                =                new_col                # Suspend list equally new variable

data_new['new_col'] = new_col # Append listing as new variable

Finally, we can consign the updated pandas DataFrame to a new CSV file as shown below:

data_new.to_csv                (                'data_new.csv'                )                # Export new pandas DataFrame

data_new.to_csv('data_new.csv') # Consign new pandas DataFrame

This CSV file will comprise our input information set up as well every bit the case list as a new variable.

Annotation that we could specify the same CSV file name inside the to_csv function to overwrite our input file. This has to exist washed with care though, considering information technology will exist difficult to restore the erstwhile file in example something goes incorrect.

Video, Further Resource & Summary

Practice you lot need farther explanations on the Python programming lawmaking of this article? Then I tin can recommend having a look at the following video on my YouTube channel. I illustrate the content of this article in the video.

The YouTube video will be added before long.

Furthermore, you might want to read the related manufactures on this website. Some articles can be constitute below:

Write pandas DataFrame to CSV File in Python
Add Cavalcade from Another pandas DataFrame in Python
Add together Cavalcade to pandas DataFrame in Python
Introduction to the pandas Library in Python
All Python Programming Tutorials

In summary: At this signal of the tutorial you lot should know how to combine and suspend a new variable to a CSV file in the Python programming language. In case y'all have additional comments or questions, don't hesitate to let me know in the comments.