Recursive Sub-Folder Search and File Retrieval

In the realm of programming, traversing directories and retrieving files can be a common task. One efficient approach is to employ a recursive algorithm to search through sub-folders and accumulate a list of files meeting specific criteria.

Problem Encountered

A user encountered a roadblock while attempting to build a list of specific files in a recursive sub-folder search. The issue stemmed from the subfolder variable pulling in a list of subfolders instead of the current folder containing the file.

Purpose of subFolder

The subFolder variable is intended to hold the name of the sub-folder under the main folder where the desired file is located.

Resolution

The key to resolving this issue lies in leveraging the "root" or "dirpath" variable instead of "subFolder." This variable holds the absolute path to the current directory being traversed during the recursion. By incorporating this path into the construction of the fileNamePath, the desired accuracy can be achieved.

import os
result = [os.path.join(dp, f) for dp, dn, filenames in os.walk(PATH) for f in filenames if os.path.splitext(f)[1] == '.txt']

Glob Module Enhancement

An alternative and efficient approach involves utilizing Python's built-in glob module. Glob excels at selecting files based on their extensions.

import os
from glob import glob
result = [y for x in os.walk(PATH) for y in glob(os.path.join(x[0], '*.txt'))]

Generator Function

For a concise and efficient implementation, one can also employ a generator function.

from itertools import chain
result = (chain.from_iterable(glob(os.path.join(x[0], '*.txt')) for x in os.walk('.')))

Python 3.4 Solution

If you're working with Python 3.4 or later, you can leverage the pathlib module's rglob() function.

from pathlib import Path
result = list(Path(".").rglob("*.[tT][xX][tT]"))

These approaches provide effective solutions for recursively searching sub-folders and compiling a list of files meeting the desired criteria, making your file retrieval tasks a breeze.