Merge CSV Files in Python with pandas 📊

Learn how to concatenate multiple CSV files into one using `pandas` in Python while avoiding leading commas in the output file.
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How to Concatenate Multiple CSV Files in Python with Pandas: Fixing Leading Commas

Are you working with multiple CSV files and need a quick way to merge them into one? If you've faced the issue of a leading comma in your output file after concatenation, you're not alone. Many developers encounter this when trying to combine data from different CSV files. Fortunately, there's a straightforward solution!

The Problem

When concatenating several CSV files using pandas, you may notice that the output contains an unwanted leading comma. This usually happens due to incorrect settings in the read_csv function, which can shift the column headers over to the right, causing misalignment. Here's an example of the output that might look familiar:

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The Solution

To resolve this issue, you need to properly configure your read_csv function. Below is a step-by-step guide for concatenating your CSV files while avoiding that pesky leading comma.

Step 1: Set Up Your Environment

You'll need to import the necessary libraries. Here's a snippet to get you started:

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Step 2: Select the Folder

Use the following code to prompt the user to select the folder containing the CSV files:

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Step 3: Read and Concatenate CSV Files

When reading your CSV files, ensure you're using index_col=False instead of index_col=None. This small change is crucial in preventing the addition of a leading comma in the output. Here’s the corrected code:

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Step 4: Export the Combined Data

Finally, write the concatenated DataFrame to a CSV file. This should create the output you desire without a leading comma:

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Conclusion

By following these simple steps, you can efficiently concatenate multiple CSV files into one cohesive data set using pandas. Remember, the key to avoiding the leading comma is ensuring the correct use of index_col. With this knowledge, you’ll be able to streamline your data processing tasks in Python effortlessly. Happy coding!