[Python-ideas] Generator unpacking

[Steven D'Aprano]

On Mon, Feb 15, 2016 at 06:53:45PM +0100, Sven R. Kunze wrote:
> On 15.02.2016 18:39, Ethan Furman wrote:
> >I /think/ I've used that trick to confirm an iterable was empty; I 
> >/know/ I've used
> >
> >[some_var] = some_var
> 
> Is that an unknown Python idiom?

No, it's exactly the same Python idiom (assignment to a list of targets) 
as we've been talking about for the last few posts. We've had examples 
with four targets, three targets, two targets and zero targets. This is 
an example with one target.

[a] = iterable

requires that the right-hand side be iterable, and after unpacking it 
must contain exactly one item, to match the one assignment target given 
on the left.


-- 
Steve