是否可以 os.walk 2 个不同的文件目录并在遍历时将它们相互比较

Question

I know it is possible to iterate over 2 lists in parallel like so...

for x, y in zip(xList, yList):
    print x, y

Is it possible to do the same with the os.walk function for 2 file directories?

Answer 1

Why not start with for x, y in zip(*map(os.walk, (dir1, dir2,))): ... ?

Edit: forgot a closing parenthesis

Answer 2

Yes you can, but the key to making it work is to perform in-place replacement to the sub-directories returned by both generators so that only sub-directories that are common to both of the current directories are retained for deeper traversal and further comparisons; otherwise the sub-directories produced by the two generators won't align with each other with zip once there is a sub-directory that's unique to one of them:

import os
for (root1, dirs1, files1), (root2, dirs2, files2) in zip(os.walk('dir1'), os.walk('dir2')):
    set1, set2 = set(dirs1), set(dirs2)
    print('Directories unique to {}: {}'.format(root1, set1 - set2))
    print('Directories unique to {}: {}'.format(root2, set2 - set1))
    dirs1[:] = dirs2[:] = set1 & set2 # crucial to retain only the common directories
    set1, set2 = set(files1), set(files2)
    print('Files unique to {}: {}'.format(root1, set1 - set2))
    print('Files unique to {}: {}'.format(root1, set2 - set1))

See demo: https://repl.it/repls/WholePessimisticSource

From the documentation of os.walk :

When topdown is True , the caller can modify the dirnames list in-place (perhaps using del or slice assignment), and walk() will only recurse into the subdirectories whose names remain in dirnames ; this can be used to prune the search...