[Python-Dev] PEP 322: Reverse Iteration

Guido van Rossum guido at python.org
Tue Nov 4 19:07:40 EST 2003

> > >     for i, value in reversed(enumerate(listofnum)):
> >
> > Sorry, this doesn't work.  enumerate() returns an iterator, reversed()
> > requires a sequence.
> I believe the assumption is that enumerate (as well as the proposed irange) 
> would grow an __reversed__ method to handle just that usage.

Ah, so it is.  Then the PEP's abstract is wrong:

This proposal is to add a builtin function to support reverse
iteration over sequences.

Also, the PEP should enumerate (:-) which built-in types should be
modified in this way, to give an impression of the enormity (or not)
of the task.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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