On Sat, Feb 6, 2010 at 11:35 AM, David <[email protected]> wrote:
> Hello again,
>
> in Knowlton's 2008 book "Python: Create, Modify, Reuse" the author makes
> frequent use of the term -1 in his code, but doesn't tell to what aim. For
> want of search terms Google is not helpful. Could someone please enlighten
> me by means of a one-liner as a reply?
>
> Example Code:
>
> for item in filelist:
> if item.find(extension)!= -1:
> snaplist.append(item)
Wayne has explained the -1; I will add that a more idiomatic way to
write this is
for item in filelist:
if extension in item:
snaplist.append(item)
or using a list comprehension (assuming snaplist starts out empty):
snaplist = [ item for item in filelist if extension in item ]
Assuming extension is a file extension, I would actually use
endswith() to filter the items:
snaplist = [ item for item in filelist if item.endswith(extension) ]
Kent
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