In Python, fastest way to build a list of files in a directory with a certain extension

Question

In Python on a GNU/Linux system, what\'s the fastest way to recursively scan a directory for all .MOV or .AVI files, and to store them in a list? <

Answer 1

Python 2.x:

import os

def generic_tree_matching(rootdirname, filterfun):
    return [
        os.path.join(dirname, filename)
        for dirname, dirnames, filenames in os.walk(rootdirname)
        for filename in filenames
        if filterfun(filename)]

def matching_ext(rootdirname, extensions):
    "Case sensitive extension matching"
    return generic_tree_matching(
        rootdirname,
        lambda fn: fn.endswith(extensions))

def matching_ext_ci(rootdirname, extensions):
    "Case insensitive extension matching"
    try:
        extensions= extensions.lower()
    except AttributeError: # assume it's a sequence of extensions
        extensions= tuple(
            extension.lower()
            for extension in extensions)
    return generic_tree_matching(
        rootdirname,
        lambda fn: fn.lower().endswith(extensions))

Use either matching_ext or matching_ext_ci with arguments the root folder and an extension or a tuple of extensions:

>>> matching_ext(".", (".mov", ".avi"))