[Python-Dev] decorate-sort-undecorate

Guido van Rossum guido at python.org
Wed Oct 15 17:17:41 EDT 2003

> On Wed, Oct 15, 2003, Guido van Rossum wrote:
> > That sounds like an extremely roundabout way of doing it; *if* there
> > had to be a way to request a stable sort, I'd say that specifying a
> > 'stable' keyword would be the way to do it.  But I think that's
> > unnecessary.
> > 
> > Given that the Jython folks had Tim's sort algorithm translated into
> > Java in half a day, I don't see why we can't require all
> > implementations to have a stable sort.  It's not like you can gain
> > significant speed over Timsort.

> But in the discussion leading up to adopting Timsort, you (or Tim, same
> difference ;-) explicitly said that you didn't want to make any doc
> guarantees about stability in case the sort algorithm changed in the
> future.

That was before Timsort had proven to be such a tremendous success.

> I don't have an opinion about whether we should keep our
> options open, but I do think there should be a clearly explicit decision
> rather than suddenly assuming that we're going to require Python's core
> sort to be stable.

OK, I pronounce on this: Python's list.sort() shall be stable.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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