How to filter files (with known type) from os.walk?

Question

I have list from os.walk. But I want to exclude some directories and files. I know how to do it with directories:

for root, dirs, files in os.wa         


        

Answer 1

Try this:

import os

skippingWalk = lambda targetDirectory, excludedExtentions: (
    (root, dirs, [F for F in files if os.path.splitext(F)[1] not in excludedExtentions]) 
    for (root, dirs, files) in os.walk(targetDirectory)
)

for line in skippingWalk("C:/My_files/test", [".dat"]):
    print line

This is a generator expression generating lambda function. You pass it a path and some extensions, and it invokes os.walk with the path, filters out the files with extensions in the list of unwanted extensions using a list comprehension, and returns the result.

(edit: removed the .upper() statement because there might be an actual difference between extensions of different case - if you want this to be case insensitive, add .upper() after os.path.splitext(F)[1] and pass extensions in in capital letters.)