How to Split CSV Data into Separate Files Using Python

Published: 25 March 2025
on channel: vlogize
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like

Learn how to efficiently split comma-separated values (CSV) files into multiple files based on repeated column headers using Python.
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How to Split CSV Data into Separate Files Using Python

Working with large datasets in CSV format can be challenging, especially when the same column names appear multiple times throughout the file. If you ever found yourself dealing with a CSV file that has repeated headers after a certain number of rows, you might be wondering how to split this data into separate files. In this post, we'll walk you through a simple solution using Python.

The Problem at Hand

Imagine you have a large CSV file structured like this:

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

In this file, the column names eno,ename, reappear after certain rows. The challenge is to split this data into three separate CSV files, each containing the data between the headers.

A Step-by-Step Solution

Here's how to break down the solution using Python's built-in CSV module.

Step 1: Read the CSV File

We will use the csv module to read the contents of the CSV file. Start by opening the file and capturing the headers.

Step 2: Check for Header Matches

We'll keep track of how many times we've encountered the headers in the file. Each time we find a match, we'll increase a counter that determines which output file to write.

Step 3: Write to Separate Files

As we read through each row, we'll write it to the corresponding file based on our counter. The following Python code implements this logic:

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

Important Note on Newlines

When using the csv.writer() function in Windows, it's crucial to add the newline="" argument. This prevents extra newline characters from being inserted between entries, which could disrupt the format of your CSV file.

Conclusion

By utilizing Python's csv module, you can efficiently split a CSV file into multiple files based on repeated header rows. This method not only saves time but also helps manage data in a much more organized way. So the next time you encounter a CSV file with repeated column names, you'll be ready to tackle the problem head-on!

Now, go ahead and try this solution on your CSV files, and let us know how it worked for you!


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