From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Pascal J. Bourguignon" Newsgroups: gmane.emacs.help Subject: Re: Sorting lines by length Date: Wed, 17 Sep 2014 04:14:26 +0200 Organization: Informatimago Message-ID: <87fvfryovx.fsf@kuiper.lan.informatimago.com> References: <87k353zptq.fsf@hornfels.zedat.fu-berlin.de> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1410920429 17082 80.91.229.3 (17 Sep 2014 02:20:29 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 17 Sep 2014 02:20:29 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed Sep 17 04:20:24 2014 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 1XU4r1-00066n-Os for geh-help-gnu-emacs@m.gmane.org; Wed, 17 Sep 2014 04:20:23 +0200 Original-Received: from localhost ([::1]:41715 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XU4r1-0003yD-1u for geh-help-gnu-emacs@m.gmane.org; Tue, 16 Sep 2014 22:20:23 -0400 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 54 Original-X-Trace: individual.net 3wOddD0hdKWGna5NRrYaUQzRXlaBySsNEVwKeR1MrqW9r9wGMs Cancel-Lock: sha1:YjA1ZDIzZWE1YmE0OTc2ZDEwYTU2NThiNWZhMWZiNDQxMzYxYzgwOA== sha1:KbtbFxaOq6T8IVxO5KrcNVE3oIU= Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) Original-Xref: usenet.stanford.edu gnu.emacs.help:207700 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:99972 Archived-At: "Loris Bennett" writes: > Hi, > > Is there a canonical way of sorting lines by length, longest first? > > I have a file with which might look like this: > > 7-Jan-2013 node025 node061 > 14-Jan-2013 node025 node034 node061 > 21-Jan-2013 node025 node034 node050 node061 > 28-Jan-2013 node025 node034 node061 > 4-Feb-2013 node025 node034 node061 > 11-Feb-2013 node025 node034 node061 > 18-Feb-2013 node034 > 25-Feb-2013 node034 > 11-Mar-2013 node025 > > I actually just need the longest line first. For the example above this > is quite easy to see, but in the real file, there are around 100 lines > and the longest might have around 1000 characters. > > My use case is reading the data into an R data frame. The number of > columns in the resulting data frame seems to be determined by the number > of items in the first line. You want the longest line. This is quite different than wanting to sort lines. Finding the longest line is a O(n) operation. Sorting lines is a O(n*log(n)) operation. (defun goto-longest-line () (interactive) (let ((max-line-start 0) (max-line-length 0)) (goto-char (point-min)) (while (< (point) (point-max)) (let ((start (point))) (forward-line) (let ((length (- (point) start))) (if (< max-line-length length) (setf max-line-length length max-line-start start))))) (goto-char max-line-start) (set-mark (+ max-line-start max-line-length)))) -- __Pascal Bourguignon__ http://www.informatimago.com/ “The factory of the future will have only two employees, a man and a dog. The man will be there to feed the dog. The dog will be there to keep the man from touching the equipment.” -- Carl Bass CEO Autodesk