[EMAIL PROTECTED] wrote:
> I do appreciate the advice, but I've got a 12 line function that does
> all of that. And it works! I just wish I understood a particular line
> of it.
>
> def getFileList(*extensions):
> import os
> imageList = []
> for dirpath, dirnames, files in os.walk('.'):
> for filename in files:
> name, ext = os.path.splitext(filename)
> if ext.lower() in extensions and not
> filename.startswith('.'):
> imageList.append(os.path.join(dirpath, filename))
> for dirname in reversed(range(len(dirnames))):
> if dirnames[dirname].startswith('.'):
> del dirnames[dirname]
>
> return imageList
>
> print getFileList('.jpg', '.gif', '.png')
>
> The line I don't understand is:
> reversed(range(len(dirnames)))
>
For a start, change "dirname" to "dirindex" (without changing
"dirnames"!) in that line and the next two lines -- this may help your
understanding.
The purpose of that loop is to eliminate from dirnames any entries
which start with ".". This needs to be done in-situ -- concocting a new
list and binding the name "dirnames" to it won't work.
The safest understandable way to delete entries from a list while
iterating over it is to do it backwards.
Doing it forwards doesn't always work; example:
#>>> dirnames = ['foo', 'bar', 'zot']
#>>> for x in range(len(dirnames)):
... if dirnames[x] == 'bar':
... del dirnames[x]
...
Traceback (most recent call last):
File "<stdin>", line 2, in ?
IndexError: list index out of range
HTH,
John
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