From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Jean Louis Newsgroups: gmane.emacs.help Subject: Re: append, push, and add-to-list. Date: Sun, 4 Jul 2021 07:35:44 +0300 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37600"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/2.0.7+183 (3d24855) (2021-05-28) Cc: help-gnu-emacs To: Hongyi Zhao Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jul 04 06:36:37 2021 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 1lztrw-0009eN-LU for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 04 Jul 2021 06:36:36 +0200 Original-Received: from localhost ([::1]:36044 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lztru-00015M-VB for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 04 Jul 2021 00:36:34 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40580) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lztrc-00015A-6b for help-gnu-emacs@gnu.org; Sun, 04 Jul 2021 00:36:16 -0400 Original-Received: from stw1.rcdrun.com ([217.170.207.13]:43673) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lztra-0003Ow-E0 for help-gnu-emacs@gnu.org; Sun, 04 Jul 2021 00:36:15 -0400 Original-Received: from localhost ([::ffff:197.157.34.164]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000057EBC.0000000060E13ABB.00003AC6; Sat, 03 Jul 2021 21:36:10 -0700 Mail-Followup-To: Hongyi Zhao , help-gnu-emacs Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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:131447 Archived-At: * Hongyi Zhao [2021-07-04 06:19]: > I've noticed there are some similar functions, i.e., append, push, and > add-to-list, for revising/updating the content of a list. But I'm > still not so clear on the specific use scenarios for them. Consider > the following command [1]: > > (push '(company-capf company-ispell) company-backends) > > What's the equivalent representations using append and add-to-list? > Which methods are preferable? It is recommended to review documentation for each function by using {C-h f} - - function add-to-list is traditionally rather used in configurations, how I see it, like (add-to-list 'load-path "/my/directory") or similar, instead, in programming code one shall rather use `push' or `cl-pushnew' as `add-to-list' adds only new unique elements; Because you use it more for configurations, then add-to-list would be: (add-to-list 'company-backends '(company-capf company-ispell)) and with append (append company-backends '(company-capf company-ispell)) -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/