os.walk，无需深入研究以下目录

How do I limit os.walk to only return files in the directory I provide it?

def _dir_list(self, dir_name, whitelist):
    outputList = []
    for root, dirs, files in os.walk(dir_name):
        for f in files:
            if os.path.splitext(f)[1] in whitelist:
                outputList.append(os.path.join(root, f))
            else:
                self._email_to_("ignore")
    return outputList

Use the walklevel function.

import os

def walklevel(some_dir, level=1):
    some_dir = some_dir.rstrip(os.path.sep)
    assert os.path.isdir(some_dir)
    num_sep = some_dir.count(os.path.sep)
    for root, dirs, files in os.walk(some_dir):
        yield root, dirs, files
        num_sep_this = root.count(os.path.sep)
        if num_sep + level <= num_sep_this:
            del dirs[:]

It works just like os.walk, but you can pass it a level parameter that indicates how deep the recursion will go.

Don’t use os.walk.

Example:

import os

root = "C:\\"
for item in os.listdir(root):
    if os.path.isfile(os.path.join(root, item)):
        print item

I think the solution is actually very simple.

use

break

to only do first iteration of the for loop, there must be a more elegant way.

for root, dirs, files in os.walk(dir_name):
    for f in files:
        ...
        ...
    break
...

The first time you call os.walk, it returns tulips for the current directory, then on next loop the contents of the next directory.

Take original script and just add a break.

def _dir_list(self, dir_name, whitelist):
    outputList = []
    for root, dirs, files in os.walk(dir_name):
        for f in files:
            if os.path.splitext(f)[1] in whitelist:
                outputList.append(os.path.join(root, f))
            else:
                self._email_to_("ignore")
        break
    return outputList

The suggestion to use listdir is a good one. The direct answer to your question in Python 2 is root, dirs, files = os.walk(dir_name).next().

The equivalent Python 3 syntax is root, dirs, files = next(os.walk(dir_name))

You could use which returns a list of names (for both files and directories) in a given directory. If you need to distinguish between files and directories, call os.stat() on each name.

If you have more complex requirements than just the top directory (eg ignore VCS dirs etc), you can also modify the list of directories to prevent os.walk recursing through them.

ie:

def _dir_list(self, dir_name, whitelist):
    outputList = []
    for root, dirs, files in os.walk(dir_name):
        dirs[:] = [d for d in dirs if is_good(d)]
        for f in files:
            do_stuff()

Note – be careful to mutate the list, rather than just rebind it. Obviously os.walk doesn’t know about the external rebinding.

for path, dirs, files in os.walk('.'):
    print path, dirs, files
    del dirs[:] # go only one level deep

The same idea with listdir, but shorter:

[f for f in os.listdir(root_dir) if os.path.isfile(os.path.join(root_dir, f))]

Felt like throwing my 2 pence in.

baselevel = len(rootdir.split("\\"))
for subdirs, dirs, files in os.walk(rootdir):
    curlevel = len(subdirs.split("\\"))
    if curlevel <= baselevel + 1:
        [do stuff]

In Python 3, I was able to do this:

import os
dir = "/path/to/files/"

#List all files immediately under this folder:
print ( next( os.walk(dir) )[2] )

#List all folders immediately under this folder:
print ( next( os.walk(dir) )[1] )

Since Python 3.5 you can use os.scandir instead of os.listdir. Instead of strings you get an iterator of DirEntry objects in return. From the docs:

Using scandir() instead of listdir() can significantly increase the performance of code that also needs file type or file attribute information, because DirEntry objects expose this information if the operating system provides it when scanning a directory. All DirEntry methods may perform a system call, but is_dir() and is_file() usually only require a system call for symbolic links; DirEntry.stat() always requires a system call on Unix but only requires one for symbolic links on Windows.

You can access the name of the object via DirEntry.name which is then equivalent to the output of os.listdir

You could also do the following:

for path, subdirs, files in os.walk(dir_name):
    for name in files:
        if path == ".": #this will filter the files in the current directory
             #code here

This is how I solved it

if recursive:
    items = os.walk(target_directory)
else:
    items = [next(os.walk(target_directory))]

...

There is a catch when using listdir. The os.path.isdir(identifier) must be an absolute path. To pick subdirectories you do:

for dirname in os.listdir(rootdir):
  if os.path.isdir(os.path.join(rootdir, dirname)):
     print("I got a subdirectory: %s" % dirname)

The alternative is to change to the directory to do the testing without the os.path.join().

You can use this snippet

for root, dirs, files in os.walk(directory):
    if level > 0:
        # do some stuff
    else:
        break
    level-=1

create a list of excludes, use fnmatch to skip the directory structure and do the process

excludes= ['a\*\b', 'c\d\e']
for root, directories, files in os.walk('Start_Folder'):
    if not any(fnmatch.fnmatch(nf_root, pattern) for pattern in excludes):
        for root, directories, files in os.walk(nf_root):
            ....
            do the process
            ....

same as for ‘includes’:

if **any**(fnmatch.fnmatch(nf_root, pattern) for pattern in **includes**):

Why not simply use a range and os.walk combined with the zip? Is not the best solution, but would work too.

For example like this:

# your part before
for count, (root, dirs, files) in zip(range(0, 1), os.walk(dir_name)):
    # logic stuff
# your later part

Works for me on python 3.

Also: A break is simpler too btw. (Look at the answer from @Pieter)

A slight change to Alex’s answer, but using __next__():

print(next(os.walk('d:/'))[2]) or print(os.walk('d:/').__next__()[2])

with the [2] being the file in root, dirs, file mentioned in other answers

root folder changes for every directory os.walk finds. I solver that checking if root == directory

def _dir_list(self, dir_name, whitelist):
    outputList = []
    for root, dirs, files in os.walk(dir_name):
        if root == dir_name: #This only meet parent folder
            for f in files:
                if os.path.splitext(f)[1] in whitelist:
                    outputList.append(os.path.join(root, f))
                else:
                    self._email_to_("ignore")
    return outputList

import os

def listFiles(self, dir_name):
    names = []
    for root, directory, files in os.walk(dir_name):
        if root == dir_name:
            for name in files:
                names.append(name)
    return names