How to merge multiple files into a new file using Python?

In the world of programming, there are often scenarios where you need to merge multiple files into a single file. This could be for various reasons such as data aggregation, report generation, or simply combining files for easier management. Python, with its rich set of libraries and easy-to-understand syntax, provides several ways to accomplish this task. In this article, we will explore different methods to merge multiple files into a new file using Python.

Understanding the Problem

Before we dive into the solutions, let's first understand the problem. Suppose we have several text files, each containing some data, and we want to merge them into a single file. The goal is to create a new file that contains the contents of all the input files combined.

Method 1: Using File Handling

The simplest way to merge files in Python is to use file handling operations. Here's a basic example:

Output

 
Hello,
world!
How are you?

In this example, we first define a list of input file names (input_files) and specify the name of the output file (output_file). We then open the output file in write mode using a with statement. Inside the for loop, we open each input file in read mode and write its contents to the output file.

Method 2: Using the shutil Module

Another approach to merge files is to use the shutil module, which provides a copyfileobj function to copy the contents of one file object to another. Here's how you can use it:

Output

 
Hello,
world!
How are you?

In this example, we use the shutil.copyfileobj function to copy the contents of each input file (infile) to the output file (outfile). This method is more efficient for large files compared to reading and writing the contents manually.

Method 3: Using the os Module

The os module in Python provides a function called os.system that allows you to execute shell commands. You can use this function to concatenate files using the cat command in Unix-like systems or the type command in Windows. Here's how you can do it:

Output

Hello,
world!
How are you?

In this example, we construct a shell command to concatenate the contents of all input files (file1.txt, file2.txt, file3.txt) into the output file (merged_file.txt). The os.system function is then used to execute this command.

Method 4: Using the glob Module

If you have a large number of input files and you want to merge all files matching a certain pattern (e.g., all .txt files), you can use the glob module to get a list of file names. Here's an example:

Output

 
Hello,
world!
How are you?

In this example, we use the glob.glob function to get a list of all .txt files in the current directory. We then merge these files into a single output file using the same approach as in Method 1.

Conclusion

Merging multiple files into a new file is a common task in programming, and Python provides several ways to accomplish it. In this article, we have covered four different methods to merge files using Python: file handling, shutil module, os module, and glob module. Each method has its advantages and can be used depending on the specific requirements of your project. I hope this article has been helpful in understanding how to merge files in Python.