Add Column from Another pandas DataFrame in Python (Example)

 

In this Python programming tutorial you’ll learn how to append a column from another pandas DataFrame.

Table of contents:

Let’s start right away!

 

Example Data & Add-On Libraries

First, we have to import the pandas library to Python:

import pandas as pd                          # Import pandas library

The following data is used as basement for this Python tutorial:

data1 = pd.DataFrame({"x1":range(20, 27),    # Create first pandas DataFrame
                      "x2":["a", "b", "c", "d", "e", "f", "g"],
                      "x3":range(48, 41, - 1)})
print(data1)                                 # Print first pandas DataFrame

 

table 1 DataFrame add column from another pandas dataframe python

 

data2 = pd.DataFrame({"y1":range(1, 8),      # Create second pandas DataFrame
                      "y2":range(8, 1, - 1)})
print(data2)                                 # Print second pandas DataFrame

 

table 2 DataFrame add column from another pandas dataframe python

 

As shown in Tables 1 and 2, the previous Python programming code has created two pandas DataFrames with different columns. Both of these data sets have the same number of rows.

 

Example: Append Column from Another pandas DataFrame

This example shows how to add a variable from another pandas DataFrame as a new column to a DataFrame in Python.

For this task, we can use the Python code below:

data_new = data1.copy()                      # Create copy of first DataFrame
data_new["y2"] = data2["y2"]                 # Add column from second to first
print(data_new)                              # Print updated DataFrame

 

table 3 DataFrame add column from another pandas dataframe python

 

After running the previous syntax the new pandas DataFrame called data_new you can see in Table 3 has been created. It contains the values of the first input data set as well as the variable y2 of the second data set.

 

Video, Further Resources & Summary

In case you need more explanations on how to union a column from another data set with an already existing pandas DataFrame, I recommend watching the following video on my YouTube channel. In the video, I’m explaining how to combine a column and a pandas DataFrame using the Python code of this page in the Python programming language:

 

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In addition, you may want to have a look at some of the other articles on my website. I have released several related articles already.

 

In this article, I have explained how to join and add a column from another pandas DataFrame in Python. In case you have additional questions on how to merge a new variable to a pandas DataFrame, tell me about it in the comments. Furthermore, please subscribe to my email newsletter in order to get updates on new tutorials.

 

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