Recursively Reading Folder Contents in Python

In Python, you can encounter issues when attempting to recursively traverse directories to read text files. A common problem is code that functions only for a single directory level.

Understanding the os.walk Function

The core of recursive folder traversal in Python lies in the os.walk() function. It iterates over a specified directory and its subdirectories, returning three values: root, subdirs, and files.

• root : The current directory being processed.
• subdirs : Directories within the current directory.
• files : Files (not directories) in the current directory.

Optimizing Folder Traversal

To traverse directories recursively, you should iterate through the list of subdirectories returned by os.walk(). For each subdirectory, you can then call os.walk() recursively to process its contents.

Improved Python Code

The example code can be modified to handle multiple directory levels:

import os
import sys

walk_dir = sys.argv[1]

for root, subdirs, files in os.walk(walk_dir):
    for subdir in subdirs:
        # Process subdirectory: call os.walk() recursively for subdir
        for sub_subdir, sub_subfiles, _ in os.walk(os.path.join(root, subdir)):
            # Process subdirectories and files in subdirectory

Additional Best Practices

• Use os.path.join() for path concatenation instead of manual string manipulation.
• Consider converting script arguments to absolute paths using os.path.abspath() for stability.
• Utilize the with statement to simplify file handling and ensure automatic cleanup.