From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id IAA01865; Mon, 28 Apr 2003 08:12:46 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id IAA02219 for ; Mon, 28 Apr 2003 08:12:45 +0200 (MET DST) Received: from teutates.kfunigraz.ac.at (TEUTATES.kfunigraz.ac.at [143.50.129.26]) by nez-perce.inria.fr (8.11.1/8.11.1) with ESMTP id h3S6CiT01931 for ; Mon, 28 Apr 2003 08:12:44 +0200 (MET DST) Received: from localhost (localhost.localdomain [127.0.0.1]) by teutates.kfunigraz.ac.at (Postfix) with ESMTP id DA3C03D222B; Mon, 28 Apr 2003 08:12:43 +0200 (CEST) Received: from teutates.kfunigraz.ac.at ([127.0.0.1]) by localhost (teutates.kfunigraz.ac.at [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 08905-06; Mon, 28 Apr 2003 08:12:43 +0200 (CEST) Received: from stud.uni-graz.at (IGAM08AV.kfunigraz.ac.at [143.50.39.35]) by teutates.kfunigraz.ac.at (Postfix) with ESMTP id B7E4F3D2225; Mon, 28 Apr 2003 08:12:42 +0200 (CEST) Message-ID: <3EACB58B.7090101@stud.uni-graz.at> Date: Mon, 28 Apr 2003 07:00:59 +0200 From: Siegfried Gonzi User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: erayo@cs.bilkent.edu.tr Cc: Markus Mottl , caml-list@inria.fr Subject: Re: [Caml-list] Easy solution in OCaml? References: <3EA8D012.8040700@stud.uni-graz.at> <20030425165944.GC6284@erle.ai.univie.ac.at> <3EABE583.802@stud.uni-graz.at> <200304271954.55400.exa@kablonet.com.tr> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at stud.uni-graz.at X-Spam: no; 0.00; siegfried:01 gonzi:01 stud:99 caml-list:01 eray:01 ozkural:01 0.0:01 foldr:01 ocaml:01 int:01 module:03 overhead:03 wrote:03 quarter:96 negligible:04 Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk > > > >Eray Ozkural wrote: > >On Sunday 27 April 2003 17:13, Siegfried Gonzi wrote: > >>quarter:: [Real] Real -> [Real] >>quarter ls nan = sum_it 0 0.0 0 ls [] >>where >> > >Ah! Why don't we have "where" in ocaml? I really miss it! > >Thanks, > Hi guys: I diged out my old Clean manuals and tried everything starting from foldr, list-comprehension, function composition (f o g o g), but I did fail and my general solution is as follows: == module stat import StdEnv meanFromList:: [Real] Real -> Real meanFromList ls nan # ls_nan = filter ((<) nan) ls # n = length(ls_nan) | n > 0 = sum(ls_nan)/toReal(n) | otherwise = nan qMeans:: [Real] Real Int -> [Real] qMeans [] nan q = [] qMeans ls nan q = [(meanFromList (take q ls) nan):(qMeans (drop q ls) nan q)] Start = qMeans [toReal(x) \\ x<-[1..100]] (-1.0) 2 == The solution needs the following Clean standard functions: filter, length, sum, take and drop. The overhead of take and drop is negligible. Regards, S. Gonzi PS: Or if you like where: == qMeans:: [Real] Real Int -> [Real] qMeans [] nan q = [] qMeans ls nan q = [(meanFromList (take q ls) nan):(qMeans (drop q ls) nan q)] where meanFromList:: [Real] Real -> Real meanFromList ls nan # ls_nan = filter ((<) nan) ls # n = length(ls_nan) | n > 0 = sum(ls_nan)/toReal(n) | otherwise = nan == > ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners