Ubuntu 16.04下os.walk获取子目录为空问题求助

Hey there! Let's break down why your code works on Windows but not Ubuntu, and how to fix it quickly.

The Root Cause #

On Linux/Unix systems like Ubuntu, the ~ character is a shell shorthand for your user's home directory—but Python's os.walk() doesn't automatically parse this symbol. When you pass '~/Downloads/pictures' directly to os.walk, it looks for a directory literally named ~ (which doesn't exist), so the loop never runs, leaving your folders list empty.

Windows handles path expansion differently (or your Windows environment might resolve ~ implicitly), which is why your original code works there.

The Fix: Expand the Path First #

You just need to expand the ~ to its full absolute path before passing it to os.walk. Here's the corrected code:

import os
# Expand ~ to the actual home directory path first
path = os.path.expanduser('~/Downloads/pictures')
folders = []
# r=root, d=directories, f = files
for r, d, f in os.walk(path):
    for folder in d:
        folders.append(os.path.join(r, folder))
for z in folders:
    print(z)

This will convert ~/Downloads/pictures to something like /home/user/Downloads/pictures, which os.walk can properly traverse. You'll now get the expected paths in your folders list.

Bonus: More Efficient Approach for Direct Subdirectories #

If you only need the immediate subdirectories (like folder1 and folder2, not nested subfolders inside them), you can skip os.walk entirely for a cleaner, faster solution:

import os
path = os.path.expanduser('~/Downloads/pictures')
# Use a list comprehension to grab only direct subdirectories
folders = [
    os.path.join(path, folder) 
    for folder in os.listdir(path) 
    if os.path.isdir(os.path.join(path, folder))
]
for z in folders:
    print(z)

This directly lists items in the target directory and filters for directories, which is more efficient if you don't need to traverse deeper.

内容的提问来源于stack exchange，提问作者Osama