[Python-ideas] About adding a new iterator methodcalled "shuffled"
steve at pearwood.info
Tue Mar 24 22:40:11 CET 2009
On Wed, 25 Mar 2009 07:20:00 am Steven D'Aprano wrote:
> On Wed, 25 Mar 2009 03:03:31 am Raymond Hettinger wrote:
> > > On Tue, Mar 24, 2009, Roy Hyunjin Han wrote:
> > >> I know that Python has iterator methods called "sorted" and
> > >> "reversed" and these are handy shortcuts.
> > >>
> > >> Why not add a new iterator method called "shuffled"?
> > You can already write:
> > sorted(s, key=lambda x: random())
> > But nobody does that. So you have a good
> > indication that the proposed method isn't needed.
> That's nice -- not as readable as random.shuffle(s) but still nice.
> And fast too: on my PC, it is about twice as fast as random.shuffle()
> for "reasonable" sized lists (tested up to one million items).
Ah crap. Ignore the above: I made an embarrassing error in my test
(neglected to actually call random inside the lambda) and so my timings
were completely wrong. The current random.shuffle() is marginally
faster even for small lists (500 items) so I withdraw my suggestion
that it be replaced.
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