From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: Testing whether a list contains at least one non-nil element Date: Tue, 25 Oct 2022 14:12:33 +0200 Message-ID: <87r0yw85la.fsf@dataswamp.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="39412"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:RREMLxmaxVItpiDCKhX4aE8Fbvs= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Oct 26 14:54:22 2022 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 1onfvK-000A2Q-Kd for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 26 Oct 2022 14:54:22 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1onfug-0003s7-UG; Wed, 26 Oct 2022 08:53:43 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onInX-0005t8-NE for help-gnu-emacs@gnu.org; Tue, 25 Oct 2022 08:12:51 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onInT-0004zi-VT for help-gnu-emacs@gnu.org; Tue, 25 Oct 2022 08:12:46 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1onInQ-0004n9-LZ for help-gnu-emacs@gnu.org; Tue, 25 Oct 2022 14:12:40 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never 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: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Wed, 26 Oct 2022 08:53:31 -0400 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: "help-gnu-emacs" Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:140399 Archived-At: Jean Louis wrote: >> I would like to test whether a list contains at least one >> non-nil element? If I do that, then I would be able to >> continue a loop where a non-nil element would mean that >> a match was found. > > Here is the test for non nil element: > > (elt (delq nil (list nil nil)) 0) ⇒ nil > > (elt (delq nil (list nil 1)) 0) ⇒ 1 Interesting question ... (cl-position-if (lambda (e) e) '(nil nil)) ; nil (cl-position-if (lambda (e) e) '(nil 1)) ; 1 -- underground experts united https://dataswamp.org/~incal