[Python-ideas] Fwd: Fwd: unpacking generalisations for list comprehension

[Greg Ewing]

Steven D'Aprano wrote:

>     t = (1, 2, 3)
>     iterable = [t]
>     [*t for t in iterable]
> 
> If you do the same manual replacement, you get:
> 
>     [1, 2, 3 for t in iterable]

Um, no, you need to also *remove the for loop*, otherwise
you get complete nonsense, whether * is used or not.

Let's try a less degenerate example, both ways.

    iterable = [1, 2, 3]
    [t for t in iterable]

To expand that, we replace t with each of the values
generated by the loop and put commas between them:

    [1, 2, 3]

Now with the star:

    iterable = [(1, 2, 3), (4, 5, 6), (7, 8, 9)]
    [*t for t in iterable]

Replace *t with each of the sequence generated by the
loop, with commas between:

    [1,2,3 , 4,5,6 , 7,8,9]

> Maybe your inability to look past your assumptions and see things from 
> other people's perspective is just as much a blind spot as our inability 
> to see why you think the pattern is obvious.

It's obvious that you're having difficulty seeing what
we're seeing, but I don't know how to explain it any
more clearly, I'm sorry.

-- 
Greg