[Python-Dev] Assignment expression and coding style: the while True case

Ivan Pozdeev vano at mail.mipt.ru
Wed Jul 4 21:38:59 EDT 2018

On 05.07.2018 3:36, Chris Angelico wrote:
> On Thu, Jul 5, 2018 at 10:33 AM, Victor Stinner <vstinner at redhat.com> wrote:
>> 2018-07-05 2:15 GMT+02:00 Chris Angelico <rosuav at gmail.com>:
>>> On Thu, Jul 5, 2018 at 10:03 AM, Victor Stinner <vstinner at redhat.com> wrote:
>>>> On the 3360 for loops of the stdlib (*), I only found 2 loops which
>>>> would benefit of assignment expressions.
>>>> It's not easy to find loops which:
>>>> - build a list,
>>>> - are simple enough to be expressed as list comprehension,
>>>> - use a condition (if),
>>>> - use an expression different than just a variable name as the list
>>>> value (value appended to the list).
>>> Are you implying that the above conditions are essential for
>>> assignment expressions to be useful, or that this defines one
>>> particular way in which they can be of value?
>> Hum, maybe I wasn't specific enough. I'm looking for "for loops" and
>> list comprehensions in stdlib which *can be* written using assignment
>> expression, like:
>>     [var for ... in ... if (var := expr)].
>> I'm not discussing if such change is worth it or not. I just counted
>> how many for loops/list comprehensions *can* be modified to use
>> assingment expressions in the stdlib.
>> Maybe I missed some loops/comprehensions, and I would be happy to see
>> more examples ;-)
> Cool. So you're looking for ones that fit a particular pattern that
> can benefit, but there are almost certainly other patterns out there.
> Just making sure that you weren't trying to say "out of 3360 loops,
> exactly 3358 of them absolutely definitely cannot be improved here".
Well, if no-one knows how to find something that can be improved, it 
can't be improved :)
> ChrisA
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