Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!bcyclone01.am1.xlned.com!bcyclone01.am1.xlned.com!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'from:addr:yahoo.co.uk': 0.04; 'subject:Python': 0.06; 'lawrence': 0.09; 'mentions': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'python': 0.11; 'language.': 0.14; 'random': 0.14; 'thread': 0.14; '8bit%:32': 0.16; 'any.': 0.16; 'finney': 0.16; 'implies': 0.16; 'pythonic': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'recognise': 0.16; 'language': 0.16; 'wrote:': 0.18; 'example': 0.22; 'putting': 0.22; 'header:User-Agent:1': 0.23; 'header:X-Complaints-To:1': 0.27; 'header:In-Reply-To:1': 0.27; "doesn't": 0.30; "i'm": 0.30; 'url:wiki': 0.31; 'url:wikipedia': 0.31; 'writes:': 0.31; "i'd": 0.34; 'problem': 0.35; 'beyond': 0.35; 'definition': 0.35; 'point.': 0.35; 'url:org': 0.36; 'so,': 0.37; 'list': 0.37; 'starting': 0.37; 'problems': 0.38; 'ben': 0.38; 'to:addr:python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'read': 0.60; 'is.': 0.60; 'hear': 0.63; 'our': 0.64; 'love': 0.65; 'skip:\xe2 10': 0.65; 'here': 0.66; 'obvious': 0.74; 'problems?': 0.91 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Mark Lawrence Subject: Re: Idiomatic backtracking in Python Date: Mon, 26 Jan 2015 08:06:16 +0000 References: <8561bumlfb.fsf@benfinney.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Gmane-NNTP-Posting-Host: host-92-24-222-48.ppp.as43234.net User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 In-Reply-To: <8561bumlfb.fsf@benfinney.id.au> X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 25 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1422259600 news.xs4all.nl 2880 [2001:888:2000:d::a6]:50235 X-Complaints-To: abuse@xs4all.nl X-Received-Bytes: 3852 X-Received-Body-CRC: 3944325508 Xref: csiph.com comp.lang.python:84593 On 26/01/2015 00:32, Ben Finney wrote: > Johannes Bauer writes: > >> So, I would like to ask if you have a Pythonic approach to >> backtracking problems? If so, I'd love to hear your solutions! > > I'm not aware of what the problem is. “Back-tracking” doesn't have a > general meaning I recognise beyond random access into a data structure. > So a Python list is the obvious starting point. > > Do you have a specific meaning of “back-tracking” that implies > particular problems that are difficult to solve? > As good a definition here http://en.wikipedia.org/wiki/Backtracking as any. As elsewhere in this thread it mentions sudoku. To me this http://norvig.com/sudoku.html is a classic example of putting theory into practice. Read and weep :) -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence