[Python-ideas] Star assignment in iterator way?
storchaka at gmail.com
Tue Nov 21 04:54:25 EST 2017
21.11.17 11:27, Kirill Balunov пише:
> Your implementation iterates seq multiple times. But iterable
> unpacking syntax works with an arbitrary iterable, and iterates it
> only once.
> Oh sorry, I know that my implementation iterates seq multiple times, I
> only provide this to show the idea. It can be much optimized at C level.
> I just want to understand if it's worth the time and effort.
You can implement the first case, but for other cases you will need a
storage for saving intermediate items. And using a list is a good option.
> And you already have mentioned a question about mutable sequence.
> If these conditions and restrictions suit you, you can use your
> good_star_exp() in your code or share it with others. But the
> semantic of iterable unpacking can't be changed.
> And how do you look at something like this (deferred star evaluation)?:
> a, ?*b, c, d = something_iterable
This will be not different from
a, *b, c, d = something_iterable
b = iter(b)
There is nothing deferred here.
The only possible benefit can be in the case
a, b, ?*c = something_iterable
But I have doubts that this special case deserves introducing a new syntax.
More information about the Python-ideas