From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: =?utf-8?Q?=C3=93scar_Fuentes?= Newsgroups: gmane.emacs.help Subject: Re: Appending to a list Date: Sun, 13 Dec 2020 22:30:52 +0100 Message-ID: <87sg89v1f7.fsf@telefonica.net> References: <877dpljtwg.fsf@fastmail.fm> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19017"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:vieuP3ZqAMJGE9t5NcaJHsFlobs= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Dec 13 22:43:32 2020 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1koZ9P-0004qi-H3 for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 13 Dec 2020 22:43:31 +0100 Original-Received: from localhost ([::1]:40972 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1koZ9O-00018K-EX for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 13 Dec 2020 16:43:30 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54728) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1koYxT-0008S5-0m for help-gnu-emacs@gnu.org; Sun, 13 Dec 2020 16:31:13 -0500 Original-Received: from static.214.254.202.116.clients.your-server.de ([116.202.254.214]:48674 helo=ciao.gmane.io) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1koYxP-00026A-0h for help-gnu-emacs@gnu.org; Sun, 13 Dec 2020 16:31:10 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1koYxE-0001m4-Nt for help-gnu-emacs@gnu.org; Sun, 13 Dec 2020 22:30:56 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 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-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:126326 Archived-At: Joost Kremers writes: > On Sun, Dec 13 2020, steve-humphreys@gmx.com wrote: >> Would appending to list like this be good? >> >> (setq bird '("Toucan" "King Fisher")) >> (setq bird (append bird ("Swift") )) > > This should result in an error, because `("Swift")` isn't quoted. You'd need: > > (setq bird (append bird '("Swift"))) > > But note that the last argument of `append` isn't copied, so it may not be a > good idea to use a literal list. > >> Or does one customarily use other constructs for >> adding to a list? > > `push` is what I would use: > > (push "Swift" bird) This does not append. > No need to use `setq` here. > > `push` won't check if the element is already in the list, though. You can use > `cl-pushnew` in that case, but be sure to load the library it's in: > > (require 'cl-lib) > (cl-pushnew "Swift" bird) Isn't that the same as (add-to-list bird "Swift" t) ?