Newbie lists question

[Gerhard Häring]

(Let's hope the supersede feature works, else please ignore the previous
posting)

On Mon, 13 Aug 2001 15:17:57 -0700, Wolfe Maykut <wolfe at spam.me.not> wrote:
>    Hi.  I'm trying to create a list on the end of a dictionary.   I'd
>like to have a single loop, but since the dictionary is dynamically
>generated it appears as if I have to test to see if the key is around
>and then treat each case differently in order to initialize the loop.
>It looks ugly.  Is there a nicer way of doing this that I'm missing?

I am not aware of a nicer solution with dictionaries, short of writing yet
another MultiDict class.

>#!/usr/bin/python
>
>import os, time, glob, string
>
>backupdir = glob.glob("/netbackups/.disks/disk*/*.out")
>
>prefixes = {}
>
>for file in backupdir:
>    filename = string.split(file, '/')[-1]
>    prefix = string.split(filename,'.')[0]
>    if prefixes.has_key(prefix):                     # This is the loop
>I think is tres' ugly
>       prefixes[prefix].append(file)
>    else:
>        prefixes[prefix] = []
>        prefixes[prefix].append(file)

I don't think this is ugly, it does even get quite nice when rewriting it:

if not prefixes.has_key(prefix):
    prefixes[prefix] = []
prefixes[prefix].append(file)

>[...]

If you insist on improving something, you could use the functions in os.path,
(like os.path.split and os.path.splitext) instead of doing the splitting
yourself ;-)

Gerhard
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