[Python-Dev] PEP 279 (original) (raw)

Aahz aahz@pythoncraft.com
Thu, 28 Mar 2002 17:06:25 -0500

On Thu, Mar 28, 2002, Guido van Rossum wrote:

Very confusing. I propose to remove the start/stop arguments, or change the spec to: def iterindexed(sequence, start=0, stop=None): i = start while stop is None or i < stop: try: item = sequence[i] except IndexError: break yield (i, item) i += 1 This reduces the validity to only sequences (as opposed to all iterable collections), but has the advantage of making iterindexed(x, i, j) iterate over x[i:j] while reporting the index sequence range(i, j) -- not so easy otherwise. The simplified version is still attractive because it allows arbitrary iterators to be passed in: def iterindexed(collection): i = 0 it = iter(collection) while 1: yield (i, it.next()) i += 1

How about doing it both ways: if you try to pass start/stop for an iterator instead of a sequence, you get an AttributeError on getindex. (I'm not proposing this, just throwing it out as an idea. It does make explaining it more difficult, which is an argument against.)

Aahz (aahz@pythoncraft.com) <*> http://www.pythoncraft.com/

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