Sequence splitting

[Paul Rubin]

Steven D'Aprano <steve at REMOVE-THIS-cybersource.com.au> writes:
> I've never needed such a split function, and I don't like the name, and 
> the functionality isn't general enough. I'd prefer something which splits 
> the input sequence into as many sublists as necessary, according to the 
> output of the key function. Something like itertools.groupby(), except it 
> runs through the entire sequence and collates all the elements with 
> identical keys.

No really, groupby makes iterators, not lists, and it you have to
develop quite a delicate sense of when you can use it without having
bugs caused by the different iterators it makes getting advanced at
the wrong times.  The concept of a split function that actually works
on lists is useful.  I'm neutral about whether it's worth having a C
version in the stdlib.