From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eric Abrahamsen Newsgroups: gmane.emacs.help Subject: Re: return first element in list with certain property Date: Mon, 20 Nov 2017 14:02:05 -0800 Message-ID: <874lpozk0y.fsf@ericabrahamsen.net> References: <8660a60zjn.fsf@zoho.com> <87mv3gzndx.fsf@ericabrahamsen.net> <86ine4y7jy.fsf@zoho.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1511215477 7534 195.159.176.226 (20 Nov 2017 22:04:37 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 20 Nov 2017 22:04:37 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Mon Nov 20 23:04:33 2017 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eGuB5-0001e8-Mx for geh-help-gnu-emacs@m.gmane.org; Mon, 20 Nov 2017 23:04:31 +0100 Original-Received: from localhost ([::1]:59978 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGuBC-0004M8-Vv for geh-help-gnu-emacs@m.gmane.org; Mon, 20 Nov 2017 17:04:39 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47637) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGu8x-0002sa-Ke for help-gnu-emacs@gnu.org; Mon, 20 Nov 2017 17:02:20 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eGu8u-0005Fr-FE for help-gnu-emacs@gnu.org; Mon, 20 Nov 2017 17:02:19 -0500 Original-Received: from [195.159.176.226] (port=46696 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eGu8u-0005FZ-80 for help-gnu-emacs@gnu.org; Mon, 20 Nov 2017 17:02:16 -0500 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1eGu8j-0001vk-SY for help-gnu-emacs@gnu.org; Mon, 20 Nov 2017 23:02:05 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 37 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:giuQsvbhVoE0jK6TSQduOnx8kHg= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 195.159.176.226 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:115015 Archived-At: Emanuel Berg writes: > Eric Abrahamsen wrote: > >> FWIW, this is essentially how seq-find works, >> and I generally use this. > > Here (my use case) it is important that the > search is linear along the list from the > beginning as the hit is almost always in the > very early section of the list. In that case there will be less difference between the two: as Drew noted, `cl-find-if' will traverse the list twice, which only becomes a big problem if the desired element is at the end of the list. But enough speculation! (setq test-front (append '(1 1 3) (make-list 1000 1))) (setq test-back (append (make-list 1000 1) '(3 1 1))) (benchmark 1000 '(seq-find (lambda (elt) (= 3 elt)) test-front)) "Elapsed time: 0.008247s" (benchmark 1000 '(cl-find-if (lambda (elt) (= 3 elt)) test-front)) "Elapsed time: 0.006165s" (benchmark 1000 '(seq-find (lambda (elt) (= 3 elt)) test-back)) "Elapsed time: 0.134623s" (benchmark 1000 '(cl-find-if (lambda (elt) (= 3 elt)) test-back)) "Elapsed time: 0.167007s" Yup, in your case it doesn't matter too much. Eric