How to Rename Files In Bulk using Python? Use Case for using Python for Automating Tasks

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You have a large number of files, and you’re asked to rename them in some sort order or naming scheme. The larger the number of files, the more time and effort required to achieve the expected outcome.

Why automate file renaming?

Obviously the time and effort spent on manually performing a tedious task like renaming each file is not productive and can easily and significantly be reduced by automating the entire process using various tools such as online platforms, AI assistants or simply Python scripts.

Python is not only a friendly-syntax programming language, it’s also exceptionally powerful and useful for automating everyday tasks. Unlike online tools and AI, leveraging Python is particularly useful for us software developers to refine our coding and problem-solving skills, or — for developers new to the language — to gain hands-on familiarity with it and simultaneously accomplish practical automation tasks.

This article is intended to demonstrate a use case of using a Python script to automate the task of renaming images with a prefix followed by a number in ascending order (e.g. image_1, image_2, image_3, …).

Prerequisite

This script requires Python 3. Don’t have Python yet? You can quickly install it from python.org on Windows or Linux

The Script

First, let’s create a file and save it as bulk_file_rename.py. Inside it, we can write the following:

import os

  def rename_in_bulk(input_directory):
    try:
      os.chdir(input_directory)

      files = [f for f in os.listdir() if f.endswith((".png", ".jpg", ".jpeg"))]

      if not files:
          print("No images were found in this directory.")
          return

      n = 1
      for old_file in files:
        _, extension = os.path.splitext(old_file)
        new_file = f"image_{n}{extension}"
        n += 1
        os.rename(old_file, new_file)
        print(f"Renamed {old_file} -> {new_file}")
      print(f"File renaming completed. Files renamed: {n-1}")
    except FileNotFoundError:
      print("Directory not found")
    except Exception as e:
      print(f"An unexpected error occurred: {e}")


  rename_in_bulk(input("Enter directory path: "))

Executing this script in a directory that contains image files will perform the renaming action.

Here’s a breakdown of the execution steps:

def rename_in_bulk(input_directory)

Defines a function, which accepts the target directory as an argument. The logic is wrapped inside a try/except block to catch potential errors.

os.chdir(input_directory)

Changes the current working folder to the target folder.

files = [f for f in os.listdir() if f.endswith((".png", ".jpg", ".jpeg"))]:

Returns a list of files in the folder but only files with these extensions .png, .jpg, .jpeg. So files contains only the images.

if not files:
    print("No images were found in this directory.")
    return

If no files were found in the folder, a message is displayed.

n = 1

Starts a counter from 1 which is to be incremented for each file. This will be used for naming images like image_1.jpg, image_2.jpg, etc.

for old_file in files:

This loops through each image in the folder.

_, extension = os.path.splitext(old_file)

Splits the filename into:

1. _: filename without extension, which will be ignored.
2. extension: the extension part (e.g. ".jpg")` which we'll be using for the new filenames.

new_file = f"image_{n}{extension}"

Here is where we construct the new names of the images: image_ + the counter n + extension.

n += 1

The counter is incremented every time we iterate through the images.

os.rename(old_file, new_file)

Function that actually renames each file by basically replacing the old file name with the new file name.

print(f"Renamed {old_file} → {new_file}")

Prints a message showing the old name → new name.

print(f"File renaming completed. Files renamed: {n-1}")

After the loop is done, this line print a message to show how many files were renamed.

except FileNotFoundError:
    print("Directory not found")

If the folder does not exist, we display a message in the except clause.

except Exception as e:
    print(f"An unexpected error occured: {e}")

This except clause catches any other error.

rename_in_bulk(input("Enter directory path: "))

Lastly, we invoke our function and ask the user to enter the folder path containing the files.

To utilize the script, simply type this command on the terminal from inside the directory where our python file is saved:

python3 bulk_file_rename.py

Insert the target folder path, hit enter and the script will take care of the rest.

The above example use case is intended to show how Python can be leveraged to automate repetitive tasks, which not only maximizes productivity but also maintains efficiency and accuracy and frees time for higher-value work. We can look at more examples in the future.

Thanks for reading!