From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: member Date: Fri, 04 Sep 2015 02:24:35 +0200 Message-ID: <87a8t3doak.fsf@debian.uxu> References: <55E5C99B.3020608@yandex.ru> <874mjccc6c.fsf@kuiper.lan.informatimago.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1441325815 11761 80.91.229.3 (4 Sep 2015 00:16:55 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 4 Sep 2015 00:16:55 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri Sep 04 02:16:45 2015 Return-path: Envelope-to: geh-help-gnu-emacs@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 1ZXegP-0008Ky-Cs for geh-help-gnu-emacs@m.gmane.org; Fri, 04 Sep 2015 02:16:45 +0200 Original-Received: from localhost ([::1]:52905 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXegP-00064c-32 for geh-help-gnu-emacs@m.gmane.org; Thu, 03 Sep 2015 20:16:45 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60682) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXegF-00064L-C4 for help-gnu-emacs@gnu.org; Thu, 03 Sep 2015 20:16:36 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZXegC-0006fh-42 for help-gnu-emacs@gnu.org; Thu, 03 Sep 2015 20:16:35 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:46891) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXegB-0006fW-Tq for help-gnu-emacs@gnu.org; Thu, 03 Sep 2015 20:16:32 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZXeg8-00086g-7c for help-gnu-emacs@gnu.org; Fri, 04 Sep 2015 02:16:28 +0200 Original-Received: from nl106-137-244.student.uu.se ([130.243.137.244]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 04 Sep 2015 02:16:28 +0200 Original-Received: from embe8573 by nl106-137-244.student.uu.se with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 04 Sep 2015 02:16:28 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Original-Lines: 23 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: nl106-137-244.student.uu.se Mail-Copies-To: never User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) Cancel-Lock: sha1:0dPsWdGBI1o8JyTATRVkPpPAKWQ= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:107016 Archived-At: "Pascal J. Bourguignon" writes: > If you just want a more concise result I'm fine using `member' as a "false predicate", and I don't think it is bad or that it should be changed. > you can use position or find instead of member. > As predicates, they're equivalent. `find' seems to be the same and thus better than `car' + member. `position' is good when what should be determined is the... position of the item. (find 2 '(1 2 3 4)) ; 2 (find 6 '(1 2 3 4 5)) ; nil (position 1 '(1 2 3 4)) ; 0 (zero-indexed; N.B. (when 0 t) ; t) (position 6 '(1 2 3 4 5)) ; nil -- underground experts united http://user.it.uu.se/~embe8573