好吧…让我们浏览一下源代码:)
文件：http ://docs.python.org/2/library/os.html#os.walk
def walk(top, topdown=True, onerror=None, followlinks=False):
islink, join, isdir = path.islink, path.join, path.isdir
try:
# Note that listdir and error are globals in this module due
# to earlier import-*.
# Should be O(1) since it's probably just reading your filesystem journal
names = listdir(top)
except error, err:
if onerror is not None:
onerror(err)
return
dirs, nondirs = [], []
# O(n) where n = number of files in the directory
for name in names:
if isdir(join(top, name)):
dirs.append(name)
else:
nondirs.append(name)
if topdown:
yield top, dirs, nondirs
# Again O(n), where n = number of directories in the directory
for name in dirs:
new_path = join(top, name)
if followlinks or not islink(new_path):
# Generator so besides the recursive `walk()` call, no additional cost here.
for x in walk(new_path, topdown, onerror, followlinks):
yield x
if not topdown:
yield top, dirs, nondirs
602392714
清零编程群