Re: [Python-ideas] iterable.__unpack__ method

Discussion in 'Python' started by Chris Angelico, Feb 24, 2013.

  1. On Mon, Feb 25, 2013 at 1:44 AM, Tim Chase
    <> wrote:
    > On 2013-02-25 01:19, Chris Angelico wrote:
    >> >>> command, subcommand = next(iterargs), next(iterargs)
    >> >>
    >> >>
    >> >> Err.... is there a language guarantee of the order of evaluation
    >> >> in a tuple, or is this just a "CPython happens to evaluate
    >> >> independent expressions left-to-right"? This is totally broken
    >> >> if the next() calls could be done in either order.
    >> >
    >> > It's a language guarantee.
    >> >
    >> > http://docs.python.org/2/reference/expressions.html#evaluation-order

    >>
    >> Ah, so it is. My bad, sorry! In that case, sure, this works. It
    >> still violates DRY though, naming the iterable twice and relying on
    >> the reader noticing that that means "take two off this one". But
    >> that's a much weaker concern.

    >
    > Your DRY/readability concern might then be addressed by writing it as
    >
    > from itertools import islice
    > # ...
    > command, subcommand = islice(iterargs, 2)
    >
    > (sorry if this was already addressed in the python-ideas@ thread,
    > since I'm not subscribed there and it looks like discussion migrated
    > to python-list@).


    Blargh, it didn't migrate, I just posted to the wrong list courtesy of
    a typo. Sorry.

    ChrisA
     
    Chris Angelico, Feb 24, 2013
    #1
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