Append two files in python

That's exactly what fileinput is for:

import fileinput
with open(outfilename, 'w') as fout, fileinput.input(filenames) as fin:
    for line in fin:
        fout.write(line)

For this use case, it's really not much simpler than just iterating over the files manually, but in other cases, having a single iterator that iterates over all of the files as if they were a single file is very handy. (Also, the fact that fileinput closes each file as soon as it's done means there's no need to with or close each one, but that's just a one-line savings, not that big of a deal.)

There are some other nifty features in fileinput, like the ability to do in-place modifications of files just by filtering each line.

As noted in the comments, and discussed in another post, fileinput for Python 2.7 will not work as indicated. Here slight modification to make the code Python 2.7 compliant

with open('outfilename', 'w') as fout:
    fin = fileinput.input(filenames)
    for line in fin:
        fout.write(line)
    fin.close()

Python makes it simple to create new files, read existing files, append data, or replace data in existing files. With the aid of a few open-source and third-party libraries, it can manage practically all of the file types that are currently supported.

We must iterate through all the necessary files, collect their data, and then add it to a new file in order to concatenate several files into a single file. This article demonstrates how to use Python to concatenate multiple files into a single file.

Using Loops

A list of filenames or file paths to the necessary python files may be found in the Python code below. Next, advanced_file.py is either opened or created.

The list of filenames or file paths is then iterated over. Each file generates a file descriptor, reads its contents line by line, and then writes the information to the advanced_file.py file.

It adds a newline character, or \n, to the new file at the end of each line.

Example - 1

Following is an example to merge multiple files nto a single file using for loop −

nameOfFiles = ["moving files.py", "mysql_access.py", "stored procedure python-sql.py", "trial.py"]
with open("advanced_file.py", "w") as new_created_file:
   for name in nameOfFiles:
      with open(name) as file:
         for line in file:
            new_created_file.write(line)
            
         new_created_file.write("\n")

Output

As an output, a new python file is created with the name “advanced_file” which has all the existing mentioned python files in it.

Example - 2

In the following code we opened the existing file in read mode and the new created file i.e. advanced_file in write mode. After that we read the that frm both the files and added it in a string and wrote the data from string to the new created file. Finally, closed the files −

info1 = info2 = ""

with open('mysql_access.py') as file:
   info1 = file.read()


with open('trial.py') as file:
   info2 = file.read()


info1 += "\n"
info1 += info2

with open ('advanced_file.py', 'w') as file:
   file.write(info1)

Output

As an output a new python file is created with the name “advanced_file” which has both the existing mentioned python files in it.

Updated on 18-Aug-2022 08:00:00

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