On Thu, Jun 17, 2021 at 3:09 PM Steven D'Aprano <[email protected]> wrote:
> On Thu, Jun 17, 2021 at 02:22:29PM -0700, Ben Rudiak-Gould wrote:
> > [*chunk for chunk in list_of_lists]
>
> What would that do?
The difference between chunk and *chunk in the expression of a list
comprehension would be the same as the difference between them in the
expressions of a starred_list.
The only thing I can guess it would do is the
> equivalent of:
>
> result = []
> for chunk in list_of_lists:
> result.append(*chunk)
>
> which is a long and obfuscated way of saying `raise TypeError` :-)
>
It would be reasonable to allow list.append to take any number of arguments
to be appended to the list, as though its definition was
def append(self, *args):
self.extend(args)
If it did, then that translation would work and do the right thing.
Some similar functions do accept multiple arguments as a convenience,
though it's not very consistent:
myset.add(1, 2) # no
myset.update([1, 2], [3, 4]) # ok
mylist.append(1, 2) # no
mylist.extend([1, 2], [3, 4]) # no
mydict.update({'a': 1}, b=2, c=3) # ok
mydict.update({'a': 1}, {'b': 2}, c=3) # no
Well, there is this:
>
> result = []
> for chunk in list_of_lists:
> *temp, = chunk
> result.append(temp)
>
> which would make it an obfuscated way to spell `list(chunk)`.
>
Unpacking would be useless in every context if you interpreted it like that.
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