From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Oleh Krehel Newsgroups: gmane.emacs.devel Subject: Re: Would seq-range and seq-mapcat be useful? Date: Fri, 30 Jan 2015 17:04:34 +0100 Message-ID: References: <878uglwmra.fsf@petton.fr> <874mr9w8at.fsf@petton.fr> <87lhkkefhn.fsf@petton.fr> <87wq448djj.fsf@yahoo.fr> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1422633899 7869 80.91.229.3 (30 Jan 2015 16:04:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 30 Jan 2015 16:04:59 +0000 (UTC) Cc: Nicolas Petton , Stefan Monnier , emacs-devel To: Nicolas Richard Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Jan 30 17:04:54 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YHE3r-000848-F1 for ged-emacs-devel@m.gmane.org; Fri, 30 Jan 2015 17:04:47 +0100 Original-Received: from localhost ([::1]:37474 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YHE3q-0001DM-Qo for ged-emacs-devel@m.gmane.org; Fri, 30 Jan 2015 11:04:46 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40865) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YHE3m-0001AC-E5 for emacs-devel@gnu.org; Fri, 30 Jan 2015 11:04:43 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YHE3f-0003TH-0C for emacs-devel@gnu.org; Fri, 30 Jan 2015 11:04:42 -0500 Original-Received: from mail-wi0-x22f.google.com ([2a00:1450:400c:c05::22f]:47980) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YHE3e-0003RP-Qt for emacs-devel@gnu.org; Fri, 30 Jan 2015 11:04:34 -0500 Original-Received: by mail-wi0-f175.google.com with SMTP id fb4so4103172wid.2 for ; Fri, 30 Jan 2015 08:04:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=eD7Se2JLXk0MBohBepN/N7aSrXpqdbPaD0YEjsysTQA=; b=Hyxr6Usw+nqqm8WHEJXXJPL0QIY5SYxMA9/usO/wQGx8iMACtKmmRewD3NNYfJYrij jxcvvxxzZC7zWqHWRMSuHnddKNX2IBTCzEKYBQD2M1QPSnZD8hwlnzVwZoyFKYqts2qh dfAtXU3S6/EZ81B3He/PCwWMUUB4ruBn1pjj5Ttri/gByvEZ9szJadaYJ/UORhrJJTbt eDpRbb3wGuniBa2llPhh283drCszzGEG0eWHkOd8GcU3Lk9ZL7iNk/V/kKXtsgtOIlka XwplZVTLXludojKxGj2y1c/A9/zRBEyG6U4CR6JTp+tYXaGduaig9Wx7TAPfyL8nzUeD o78A== X-Received: by 10.180.37.197 with SMTP id a5mr6166724wik.2.1422633874166; Fri, 30 Jan 2015 08:04:34 -0800 (PST) Original-Received: by 10.27.137.137 with HTTP; Fri, 30 Jan 2015 08:04:34 -0800 (PST) In-Reply-To: <87wq448djj.fsf@yahoo.fr> X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:400c:c05::22f X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:182067 Archived-At: On Fri, Jan 30, 2015 at 4:59 PM, Nicolas Richard wrote: > Oleh Krehel writes: >> Is this already somewhere? > > IDK, but I often wrote this kind of snippet for that purpose : > > (defun yf/seq-group-by (fn lst) > (let ((hash (make-hash-table :test 'equal))) > (dolist (elm lst) > (push elm (gethash (funcall fn elm) hash))) > hash)) > > (yf/seq-group-by > #'car > '(("a" 1) > ("b" 2) > ("b" 5) > ("c" 1))) > => #s(hash-table size 65 test equal rehash-size 1.5 rehash-threshold 0.8 data > ("a" > (("a" 1)) > "b" > (("b" 5) > ("b" 2)) > "c" > (("c" 1)))) > > -- > Nicolas Richard Mine's faster: (defmacro util-timeit (expr) (let ((t-beg (float-time)) (res (dotimes (i 10000) (eval expr))) (t-end (float-time))) (/ (- t-end t-beg) 10000))) (util-timeit (yf/seq-group-by #'car tmp)) 0.0003461523771286011 0.00033148398399353025 0.00032957537174224856 (util-timeit (seq-group-by #'car tmp)) 0.00019227066040039062 0.00018899762630462645 0.0001775247573852539