[Python-Dev] Informal educator feedback on PEP 572 (was Re: 2018 Python Language Summit coverage, last part)

Greg Ewing greg.ewing at canterbury.ac.nz
Wed Jun 27 20:03:32 EDT 2018

Ivan Pozdeev via Python-Dev wrote:
> This isn't as messy as you make it sound if you remember that the 
> outermost iterable is evaluated only once at the start and all the 
> others -- each iteration.
> Anyone using comprehensions has to know this fact.

That fact alone doesn't imply anthing about the *scopes* in which
those iterators are evaluated, however.

Currently the only situation where the scoping makes a difference
is a generator expression that isn't immediately used, and you can
get a long way into your Python career without ever encountering
that case.


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