Re: Help me understand this iterator

LaundroMat wrote:

[me hitting send too soon]

Now, if I look at this script step by step, I don't understand:

- where the "while 1:"-loop is quitted.

class DirectoryWalker:
# a forward iterator that traverses a directory tree

def __init__(self, directory):
self.stack = [directory]
self.files = []
self.index = 0

def __getitem__(self, index):
while 1:
try:
file = self.files[self.index]
self.index = self.index + 1
except IndexError:
# pop next directory from stack
self.directory = self.stack.pop()

If self.stack is empty, pop() will raise an IndexError which terminates both
the 'while 1' loop in __getitem__() and the enclosing 'for file in ...'
loop

self.files = os.listdir(self.directory)
self.index = 0
else:
# got a filename
fullname = os.path.join(self.directory, file)
if os.path.isdir(fullname) and not
os.path.islink(fullname):
self.stack.append(fullname)
return fullname

The return statement feeds the next file to the for loop.

Peter

.

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