[Python-3000] Set literal
Guido van Rossum
guido at python.org
Mon Jan 28 17:02:24 CET 2008
Please don't reopen this. There are good reasons for 'set' to be the
default set type and 'frozenset' to appear like a poor cousin. For
one, their naming. This was all reasoned out long, long ago, in Python
2.3 with the sets module. If you insist I will try to write it up all
again, but I'd rather you believe that we weren't crazy back then.
Raymond's about-face suggests that there are plenty of dead alleys
that lead the traveler astray by appearing to be a shortcut to their
On Jan 27, 2008 9:38 PM, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> Guido van Rossum wrote:
> > On Jan 26, 2008 8:39 PM, Raymond Hettinger <python at rcn.com> wrote:
> >>However, my support for it has waned anyway. The notation is also
> >>used for set comprehension and those should be mutable.
> > Cool. That saves us a PEP. Vive le status quo.
> You're changing your mind back again just like that? That's
> disappointing -- I was fairly convinced there as well.
> Another possibility would be to drop set comprehension
> syntax and just require people to use set(genexp).
> Or have set comprehensions produce frozensets and require
> set(genexp) to get a mutable set.
> On the face of it, it's not clear to me that the result of
> a set comprehension should necessarily be mutable.
> When I think about how I have used list comprehensions,
> mutability of the resulting list isn't usually a requirement.
> I don't expect this would be different with sets.
> Python-3000 mailing list
> Python-3000 at python.org
> Unsubscribe: http://mail.python.org/mailman/options/python-3000/guido%40python.org
--Guido van Rossum (home page: http://www.python.org/~guido/)
More information about the Python-3000