Ed Singleton wrote:
> Is it possible to access the next and previous items during an iteration?
There is nothing built in to support this directly.
> I'm currently using:
>
> prev = 0
> current = 0
> next = 0
> for page in folder:
> prev = current
> current = next
> next = page
> if current:
> if prev:
> #add link to previous page
> #add link to next page
> if current:
> if prev:
> #add link to previous page
> #add link to next page
I think there is a bug here - when the loop exits, prev, current and next will
all be
valid with next containing the last page. You have already added the links to
current, it
is next that needs a link to the previous page.
>
> But this seems a really awkward way to do it.
>
> I've considered iterating and dumping them all into a list and then
> iterating through the list, but that also seems awkward (having to
> iterate twice).
You don't say what kind of object folder is. If it is a directory listing e.g.
from
os.listdir() then it is already a list. In any case you should be able to make
a list
without an explicit iteration using
pages = list(folder)
>
> Is there a nice way to do it?
How about this:
pages = list(folder) # make sure we have a list
for i, page in enumerate(pages):
if i > 0:
previous = pages[i-1]
# add link to previous
if i+1 < len(pages):
next = pages[i+1]
# add link to next
Kent
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