From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Neon Absentius Newsgroups: gmane.emacs.help Subject: Re: regexp to collapse multiple blank lines into one Date: Mon, 10 Oct 2005 17:28:45 +0000 Message-ID: <20051010172845.GX29712@SDF.LONESTAR.ORG> References: <9rd2f.11472$vw6.9111@newsread1.news.atl.earthlink.net> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1128965460 4904 80.91.229.2 (10 Oct 2005 17:31:00 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 10 Oct 2005 17:31:00 +0000 (UTC) Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Mon Oct 10 19:30:58 2005 Return-path: Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1EP1Sk-0006ML-UU for geh-help-gnu-emacs@m.gmane.org; Mon, 10 Oct 2005 19:29:24 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1EP1Sk-0006h8-Cv for geh-help-gnu-emacs@m.gmane.org; Mon, 10 Oct 2005 13:29:22 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1EP1ST-0006gx-85 for help-gnu-emacs@gnu.org; Mon, 10 Oct 2005 13:29:05 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1EP1SP-0006fd-J8 for help-gnu-emacs@gnu.org; Mon, 10 Oct 2005 13:29:05 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1EP1SP-0006fF-6R for help-gnu-emacs@gnu.org; Mon, 10 Oct 2005 13:29:01 -0400 Original-Received: from [192.94.73.21] (helo=sdf.lonestar.org) by monty-python.gnu.org with esmtp (Exim 4.34) id 1EP1SP-0002lU-2M for help-gnu-emacs@gnu.org; Mon, 10 Oct 2005 13:29:01 -0400 Original-Received: from sdf.lonestar.org (IDENT:absent@ukato.freeshell.org [192.94.73.7]) by sdf.lonestar.org (8.13.1/8.12.10) with ESMTP id j9AHSjkZ014956 for ; Mon, 10 Oct 2005 17:28:45 GMT Original-Received: (from absent@localhost) by sdf.lonestar.org (8.13.1/8.12.8/Submit) id j9AHSj07015768 for help-gnu-emacs@gnu.org; Mon, 10 Oct 2005 17:28:45 GMT Original-To: help-gnu-emacs@gnu.org Mail-Followup-To: Neon Absentius , help-gnu-emacs@gnu.org Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 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-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:30107 Archived-At: On Mon, Oct 10, 2005 at 10:35:01AM -0600, Kevin Rodgers wrote: > B. T. Raven wrote: > > "Neon Absentius" wrote in message > > news:mailman.10556.1128865819.20277.help-gnu-emacs@gnu.org... > >>The following seems to work > >> > >>C-M-% \(^C-qC-j\)+ RET \1 RET > >> > >>Provided of course that your lines are really blank and do not contain > >>any spaces, tabs etc. > > > > Thanks F.L., P.D., N.A. Neon's solution seems the easiest to me. I need > > this only because I can't get control chars into the replacement string. > > The replacement can be a bare RET but you can't replace with less than > > nothing, i.e. replacing a regexp with nothing and then backspacing to > > get rid of the blank line. > > Why can't you use the same technique to put a control character into the > replacement string as Neon suggests for the search string/regexp > (namely, C-q)? > Actually that also works. The reason I used "\1" is that I had already grouped the regexp so it saved me typing. > I'll admit, I don't understand why that solution works: it appears to > replace the matched sequence of LFD characters with itself, instead of > replacing it with just a single LFD character (or nothing at all, > depending on the desired result). > I don't understand what you don't understand :) My solutions replaces one or more occurences of a regexp with a single occurence. Perhaps you are worried abour efficiency? that if there is a single occurence I replace it with itself? In that case you are right. A better solution would be better: C-M-% \(^C-qC-j\)\{2,\} RET \1 RET -- There is no national science just as there is no national multiplication table; what is national is no longer science. -- Anton Checov