[Python-Dev] Examples for PEP 572
Sven R. Kunze
srkunze at mail.de
Wed Jul 4 16:07:44 EDT 2018
On 04.07.2018 21:18, Steven D'Aprano wrote:
> Read the Appendix to the PEP:
Yes, I did after I realized where that example came from. But my point
was actually to understand the evaluation order because Uncle Timmy
won't be around to explain when new code appears.
> And no, total is not always not equal to total.
Err, yeah. Double negation rules. ;-)
> I read it as:
> while total != updated total:
> do stuff
> and find it easier to follow than having to juggle the extra
> book-keeping "old" variable in the original code.
updated_total rocks. Reminds me of those pattern, we usually use in
What just confused me is the evaluation order. It seems to me that it's
like left-to-right first and then assignment expression.
Using some math-style-inspired markers (execution-irrelevant) would be cool:
while total != (total' := total + term):
total and total' can be different at the same whereas total is total (at
least in my mental model).
But it seems I need to adapt here.
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