[Python-Dev] PEP 572: Assignment Expressions
Nick Coghlan
ncoghlan at gmail.com
Wed Apr 18 06:23:39 EDT 2018
On 18 April 2018 at 11:35, Tim Peters <tim.peters at gmail.com> wrote:
> And, for some reason, I find this even worse:
>
> while ((x, y) := func_returning_tuple())[1] is not None:
> ...
>
> The rub there: I gave `y` a name but can't use it in the test?!
>
> And those are the same kinds of headaches I saw over & over in my own
> "fancier" code: stuff that's already perfectly clear would become
> more obscure instead.
Whereas I think:
while (s := func_returning_tuple())[1] is not None:
s = x, y
...
compares favourably with the loop-and-a-half version.
It does make the guarantee that "y is not None" harder to spot than it
is in the loop-and-a-half version, though.
Cheers,
Nick.
--
Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia
More information about the Python-Dev
mailing list