Recursive list comprehension
tjreedy at udel.edu
Thu Dec 9 04:25:27 CET 2004
"Steven Bethard" <steven.bethard at gmail.com> wrote in message
news:LoNtd.465310$wV.295778 at attbi_s54...
> What is the getnext protocol? Is that the same thing that the iter()
> docs call the sequence protocol?
Yes. (I meant to write getitem rather than getnext.)
> Because this definitely still works with itertools:
Yes, not because itertools are cognizant of sequence objects but because
itertools apply iter() to inputs and because iter() currently accomodates
sequence-protocol objects as well as iterable-protocol objects by wrapping
the former with builtin <iterator> objects. I expect that may change if
and when the builtin C-coded types are updated to have __init__ methods.
This is a ways off, if ever, but I think the general advice for user code
is to use the newer protocol. So, for the purpose of writing new code, I
think it justified to forget about or at least ignore the older iteration
Terry J. Reedy
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