Combine Multiple Csv Files Into One

In our previous tutorial, you had learned how to merge multiple CSV files using Python built-in functions. Today, we’ll demonstrate how to use Pandas to merge CSV files and explain with a fully working example.

Merge Multiple csv files into one dataset Posted 11:13 AM (5565 views) Hi, I try to. A) create a dataset of non consecutive.csv files in a certain folder. CSV is a data format that can be used to store transcripts, orders and other data. Sometimes you need to merge multiple CSV files statistically. Doing so manually is very tedious. This tool can perform fast, bulk merging of multiple CSV files and produce an output as a CSV file. I got a call from a friend who wanted to combine multiple Excel files into one Excel workbook. He had a lot of files in a folder and he wanted to get all the worksheets from all the workbooks into one single workbook. While this can be done manually, it would be time-consuming and error-prone. However, a simple VBA code can do this in a few.

We’ll start by telling you – what is the use of Pandas? It is a library written in Python for data munging and analysis. It provides highly optimized data structures and high-performing functions for working with data.

Pandas handle data from 100MB to 1GB quite efficiently and give an exuberant performance. However, in case of BIG DATA CSV files, it provides functions that accept chunk size to read big data in smaller chunks.

Python Using Pandas to Merge CSV Files


  • 1 Python script to merge CSV using Pandas

When you have a set of CSV files in a multitude of 100s or 1000s, then it is impossible to combine them manually. But, if you try to do so, then it may lead to incorrect merge and a lot of errors. In the below section, we are providing a step by step mechanism to combine multiple CSV files. We’ll be creating a simple Python script and use the Pandas library.

Python script to merge CSV using Pandas

Include required Python modules

How to merge pst files

In our Python script, we’ll use the following core modules:

  • OS module – Provides functions like copy, delete, read, write files, and directories.
  • Glob module – Provides glob function to list files and directories in Python.
  • Pandas – Provides functions to merge multiple CSV files in quick time.

To sum up, check out the below coding snippet. It loads the required modules and sets the working dir for our testing.

Quickly combine multiple excel files

Prepare a list of all CSV files

In this step, we have to find out the list of all CSV files. Therefore, we’ll use the glob() function and give it the “.csv” pattern to list matching the target.

Below is a piece of code to list all files matching “.csv” pattern.

Check out – Python to List All Files in a Directory

Concatenate to produce a consolidated file

It is the last step where we have to call Pandas concat() to return a consolidate object. After that, we convert the result back to a single CSV file. It generates the final output in the current working directory.

Let’s check out the final piece of code that does our task.

Combine Multiple Csv Files Into One Excel

Full script code

How To Combine Multiple Csv Files Into One


We hope that you now know how to use the Pandas library to merge CSV files. Also, you can write a fully working Python script. It will help you combine multiple files quickly.