Sorry for not being clear from the beginning and for not using clear
variable names.
Problem context:
import os
dirs_exclude = set(('a', 'b', 'e'))
for root, dirs, files in os.walk('python/Lib/email'):
# Task:
# delete from "dirs" the directory names from "dirs_exclude"
# case-insensitive
The solution so far is:
for i in xrange(len(dirs), 0, -1):
if dirs[i-1].lower() in dirs_exclude:
del dirs[i-1]
I am looking for a nicer solution.
Thanks a lot,
Ray
Tim Chase wrote:
>> Yeah, I ended up doing a similar kind of loop. That is pretty messy.
>>
>> Is there any other way?
>
> I've already provided 2 (or 3 depending on how one counts)
> solutions, each of which solve an interpretation of your original
> problem, neither of which involve more than 3 lines of fairly
> clean code. Perhaps a little more context regarding what you
> *want* to do would help. However, I suspect that answer is
> "there is no *cleaner* way to do it".
>
> Unless you're modifying an existing list that is referenced
> elsewhere, the reassignment (l = [x for x in l ...]) solution
> should work just fine. Thus, unless you have a situation akin to:
>
> g = l
> l = [x for x in l if x.lower() not in s]
> assert(thing_from_s not in g)
>
> then just reassign "l". If not, use the loop. It's that easy
> and clean. Don't try to opaquify it by collapsing it further.
> Perhaps, if your loop is messy, use my clean loop suggestion.
>
> -tkc
>
>
>
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