From: Thierry Volpiatto <thierry.volpiatto@gmail.com>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: can `shuffle-vector' be moved?
Date: Fri, 13 May 2011 19:13:08 +0200 [thread overview]
Message-ID: <87aaeqed7f.fsf@gmail.com> (raw)
In-Reply-To: <jwvei427lcy.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Fri, 13 May 2011 11:00:10 -0300")
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> I don't know where it should live, but cookie1.el doesn't seem like the
>>> right place.
>>>
>>> It should be documented in "(elisp) Vector Functions" as well.
>>>
>>> Let me know if I should do this, please.
>>>
>>> Also this loop call from Pascal Bourguignon is a nice CL alternative to
>>> `shuffle-vector', though it uses the same algorithm:
>>>
>>> (defun shuffle (vector)
>>> "Re-orders randomly the vector."
>>> (loop
>>> for i from (1- (length vector)) downto 1
>>> do (rotatef (aref vector i) (aref vector (random i)))))
>
>> Nice.
>> Why is this limited to vectors? with elt it could work also with lists.
>
> Its algorithmic performance on lists would be poor (O(N²)).
> You want a different algorithm for lists.
Ok. Thanks.
--
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997
prev parent reply other threads:[~2011-05-13 17:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-12 19:58 can `shuffle-vector' be moved? Ted Zlatanov
2011-05-13 2:03 ` Leo
2011-05-13 2:10 ` Stefan Monnier
2011-05-13 3:49 ` Ted Zlatanov
2011-05-13 13:57 ` Stefan Monnier
2011-05-13 3:53 ` Ted Zlatanov
2011-05-13 6:00 ` Kevin Rodgers
2011-05-13 14:48 ` Ted Zlatanov
2011-05-13 15:26 ` Stefan Monnier
2011-05-13 16:22 ` Ted Zlatanov
2011-05-13 16:47 ` Stefan Monnier
2011-05-13 16:51 ` Ted Zlatanov
2011-05-13 6:19 ` Thierry Volpiatto
2011-05-13 14:00 ` Stefan Monnier
2011-05-13 14:38 ` Ted Zlatanov
2011-05-13 17:13 ` Thierry Volpiatto [this message]
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