[Python-Dev] itertools addition: getitem()

[Guido van Rossum]

How important is it to have the default in this API? __getitem__()
doesn't have a default; instead, there's a separate API get() that
provides a default (and I find defaulting to None more manageable than
the "_default = object()" pattern).

--Guido

On 7/8/07, Walter Dörwald <walter at livinglogic.de> wrote:
> I'd like to propose the following addition to itertools: A function
> itertools.getitem() which is basically equivalent to the following
> python code:
>
> _default = object()
>
> def getitem(iterable, index, default=_default):
>     try:
>        return list(iterable)[index]
>     except IndexError:
>        if default is _default:
>           raise
>        return default
>
> but without materializing the complete list. Negative indexes are
> supported too (this requires additional temporary storage for abs(index)
> objects).
>
> The patch is available at http://bugs.python.org/1749857
>
> Servus,
>     Walter
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-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)