[Tutor] list concatenation

[Gonçalo Rodrigues]

----- Original Message -----
From: "Lance" <lbrannma@cablespeed.com>
To: "Tutor" <tutor@python.org>
Sent: Wednesday, February 05, 2003 3:37 PM
Subject: [Tutor] list concatenation


> Hi All,
>
> What's the fastest way to concatenate the same string to all elements of a
> list? I have a list of filenames and want to concatentate the path, a
common
> path, to each of them.
>

There aren't many choices really. Supposing lst is your list and pathname is
the path to concatenate, use the os.path module as in:

import os

#Avoid recurrent name resolution.
joinpath = os.path.join
#Change list in place => avoid allocation of new list.
for i in range(len(lst)):
    lst[i] = joinpath(lst[i], pathname)

If you need to keep the old list lst a list comprehension will do, as in:

newlist = [joinpath(path, pathname) for path in lst]

> Thanks,
> Lance
>

Hope it helps,
G. Rodrigues