Скачать или смотреть Transform Your DataFrame: Convert Columns to Rows Using Python Pandas

Learn how to convert specific column sets in a pandas DataFrame into rows, while repeating the values in other columns. This guide provides a step-by-step solution using Python.
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This video is based on the question https://stackoverflow.com/q/74078937/ asked by the user 'Harshit Jain' ( https://stackoverflow.com/u/8572755/ ) and on the answer https://stackoverflow.com/a/74079348/ provided by the user 'Bushmaster' ( https://stackoverflow.com/u/15415267/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Transform Your DataFrame: Convert Columns to Rows Using Python Pandas

In the world of data analysis, the ability to manipulate data formats is crucial. Whether you’re cleaning a dataset for better insights or preparing it for machine learning, knowing how to transform your data is essential. One common problem you might encounter is needing to convert specific columns into rows while repeating other column values. In this post, we’ll tackle this problem using Python and the powerful pandas library.

The Problem: DataFrame Restructuring

Imagine you have a DataFrame containing multiple columns, which represent different subjects and grades for various individuals. Your DataFrame may look something like this:

IDSCHOOLName1Name1 Subject1Name1 Grade1Name1 Subject2Name1 Grade2Name2Name2 Subject1Name2 Grade1Name2 Subject2Name2 Grade21S1Mr. ABCMath6Science7Mr. XYZSocial8EVS92S2Mr. PQRMath10Science11Mr. KLMSocial8EVS9Your goal is to transform this data into a more structured format where each subject and corresponding grade appear as individual rows, while keeping the ID and SCHOOL consistent for each entry. The desired format would be:

IDSCHOOLNameSubjectGrade1S1Mr. ABCMath61S1Mr. ABCScience71S1Mr. XYZSocial81S1Mr. XYZEVS92S2Mr. PQRMath102S2Mr. PQRScience112S2Mr. KLMSocial82S2Mr. KLMEVS9The Solution: Step-by-Step Guide

To achieve the desired transformation, we can use pandas to segment our DataFrame into manageable parts and then concatenate those parts back together in the required format. Below is a step-by-step walkthrough.

Step 1: Create Your DataFrame

Let's begin by assuming your data is already loaded into a pandas DataFrame named df.

Step 2: Separate Data Into Chunks

Next, we will create separate DataFrames to handle each set of names, subjects, and grades. The following code illustrates this:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Rename Columns

To standardize the columns, we need to rename them for all the DataFrames created earlier. This can be done using the following code:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Concatenate DataFrames

Now that we have separate DataFrames with uniform column names, we can concatenate them into a single DataFrame:

[[See Video to Reveal this Text or Code Snippet]]

Output

The final DataFrame will look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Transforming data from a wide format to a long format can be challenging but achievable with Python's pandas library. By segmenting your DataFrame into manageable parts and then combining them, you can efficiently reshape your data according to your needs. Next time you encounter a similar challenge, remember this approach!

For more data manipulation techniques and tips, stay tuned for our upcoming posts.