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

[Greg Ewing]

Steven D'Aprano wrote:
> Are you now supporting my argument that starring the list comprehension 
> expression isn't meaningful?

The context it's in (a form of list display) has a clear
meaning for a comma-separated list of values, so there
is a reasonable interpretation that it *could* be given.

> py> iterable = [(1, 'a'), (2, 'b')]
> py> [(100, *t) for t in iterable]
> [(100, 1, 'a'), (100, 2, 'b')]

The * there is in the context of constructing a tuple,
not the list into which the tuple is placed.

The difference is the same as the difference between
these:

 >>> t = (10, 20)
 >>> [1, (2, *t), 3]
[1, (2, 10, 20), 3]
 >>> [1, 2, *t, 3]
[1, 2, 10, 20, 3]

-- 
Greg