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Wed Nov 5 11:48:31 EST 2003 · https://mail.python.org/pipermail/python-dev/2003-November/040013.html

On Wed, 2003-11-05 at 15:56, Alex Martelli wrote:
> def reversed(sequence):
>     for x in xrange(len(sequence)-1, -1, -1): yield sequence[x]
> 
> no __reversed__, no complications, "no nuttin'".

If I was adding this as a library routine, I'd do:

def reversed(sequence):
    try:
        seqlen = len(sequence)
    except TypeError:
        sequence = list(sequence)
        seqlen = len(sequence)

    for x in xrange(seqlen-1, -1, -1):
        yield sequence[x]

OK, inefficient for iterators on long sequences, but it works with
enumerate() etc and needs no changes to existing types.

Mark

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Showing content from https://mail.python.org/pipermail/python-dev/2003-November/040013.html below:

[Python-Dev] Re: PEP 322: Reverse Iteration