[Python-ideas] iterable.__unpack__ method
Chris Angelico
rosuav at gmail.com
Sun Feb 24 09:19:02 EST 2013
On Mon, Feb 25, 2013 at 1:16 AM, Steven D'Aprano <steve at pearwood.info> wrote:
> On 24/02/13 23:59, Chris Angelico wrote:
>>
>> On Sun, Feb 24, 2013 at 10:25 PM, Larry Hastings <larry at hastings.org>
>> wrote:
>>>
>>> Or
>>>
>>> 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.
ChrisA
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