How to use OS with Python List Comprehension

One such module is the ‘os’ module, which allows interaction with the operating system. When combined with list comprehensions, the ‘os’ module becomes a potent tool for handling file and directory operations concisely and expressively. In this article, we will see how we can use the os module with list comprehension in Python.

OS with Python List Comprehension

Below are some of the example for using os with List Comprehension in Python:

• Listing Files in a Directory
• Filtering Files with a Specific Extension
• Getting Subdirectories

File Structure

file structure

Listing Files in a Directory

In this example, in below code the Python OS module to list and display the names of files within the specified ‘gfg’ directory. The ‘list_files’ function employs list comprehension to filter only files (not directories) and then prints the resulting list.

Python3

# importing os module
import os

def list_files(directory_path):

    # list comprehension
    files = [file for file in os.listdir(directory_path) if os.path.isfile(
        os.path.join(directory_path, file))]

    # displaying the names available
    print("List of files in the directory:")
    for file in files:
        print(file)


# main function
if __name__ == "__main__":
    directory_path = "gfg"
    list_files(directory_path)

Output:

List of files in the directory:
four.py
one.txt
three.txt
two.txt

Filtering Files with a Specific Extension

In this example, below code uses the ‘os’ module to filter and display the names of files with the ‘.txt’ extension within the specified ‘gfg’ directory. The ‘filter_file’ function employs list comprehension to select only files with the target extension, and then it prints the resulting list.

Python3

# importing os module
import os

def filter_file(directory_path, target_extension):

    # list comprehension
    filtered_files = [file for file in os.listdir(directory_path) if file.endswith(
        target_extension) and os.path.isfile(os.path.join(directory_path, file))]

    # displaying the names available
    print(f"List of {target_extension} files in the directory:")
    for file in filtered_files:
        print(file)


# main function
if __name__ == "__main__":
    directory_path = "gfg"
    target_extension = ".txt"
    filter_file(directory_path, target_extension)

Output:

List of .txt files in the directory:
one.txt
three.txt
two.txt

Getting Subdirectories

In this example, below code uses the ‘os’ module to retrieve and display the names of subdirectories within the specified ‘gfg’ parent directory. The ‘get_subdirectories’ function employs list comprehension to filter only items that are directories, and then it prints the resulting list.

Python3

# importing os module
import os

def get_subdirectories(parent_directory):

    # list comprehension
    subdirectories = [subdir for subdir in os.listdir(
        parent_directory) if os.path.isdir(os.path.join(parent_directory, subdir))]

    # displaying the names available
    print("List of subdirectories in the parent directory:")
    for subdir in subdirectories:
        print(subdir)


# main function
if __name__ == "__main__":
    parent_directory = "gfg"
    get_subdirectories(parent_directory)

Output:

List of subdirectories in the parent directory:
gfg1
gfg2