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: How to delete all nil properties from a plist? Date: Sun, 02 Aug 2015 18:21:48 +0200 Organization: Informatimago Message-ID: <87wpxdu0df.fsf@kuiper.lan.informatimago.com> References: <87oaiq3buh.fsf@mbork.pl> <87mvya3bij.fsf@mbork.pl> <871tfmv5d5.fsf@kuiper.lan.informatimago.com> 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 1438532723 6401 80.91.229.3 (2 Aug 2015 16:25:23 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 2 Aug 2015 16:25:23 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Aug 02 18:25:19 2015 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 1ZLw4a-0003UK-Ka for geh-help-gnu-emacs@m.gmane.org; Sun, 02 Aug 2015 18:25:16 +0200 Original-Received: from localhost ([::1]:56381 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZLw4Z-00009N-Uo for geh-help-gnu-emacs@m.gmane.org; Sun, 02 Aug 2015 12:25:15 -0400 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 46 Original-X-Trace: individual.net 9+UdGfz1qq01ND2p03Td3AgoK403Wcc/7Z8Ehd97iVD3YVY6L6 Cancel-Lock: sha1:MzhiN2U4ZjI3ZGEzZTIxNTQ1Nzk0YjBkMTkyZTFlMDNmOWY3NWZhOQ== sha1:61RKV4wqUWHPcJqDYi0NQqD5TRQ= 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:213926 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:106211 Archived-At: Rusi writes: > On Sunday, August 2, 2015 at 7:06:24 AM UTC+5:30, Pascal J. Bourguignon wrote: >> Emanuel Berg writes: >> >> > Marcin Borkowski writes: >> > >> >>> Hi all, so I'm still using plists, though I'm less >> >>> and less sure that they are actually better than >> >>> alists for my use-case. Now I need to delete all >> >>> properties whose value is nil. I'm using this >> >>> function: >> > >> > Try this: >> > >> > (require 'cl) >> > >> > (defun plist-drop-nil-props (l) >> > (let((new) >> > (prop nil) ) >> > (cl-loop for x in l >> > do (if (or (setq prop (not prop)) x) >> > (setq new (append new (list x))) >> > (setq new (butlast new)))) >> > new)) >> >> This is horrible. Again, you can't prevent yourself writing O(n²) code >> when O(n) would do perfectly. > > Hey Pascal! > If O(n²) is 'horrible' what is O(n³)? And O(n⁴) ? > And the stuff in NP? > [I suppose the french lexicon has many adjectives...] What's horrible is the ratio between the actual O(.) over the possible O(.). > BTW: Thanks for being civilized/cultured and using a non-ASCII character ² > when it is appropriate. Vive la Unicode! -- __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