Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!news.stack.nl!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!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 0.001 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'languages.': 0.04; 'subject:Python': 0.06; 'expressions': 0.07; 'mentioned,': 0.07; 'problem:': 0.07; 'string': 0.09; '[1]:': 0.09; '[2]:': 0.09; '[3]:': 0.09; 'mentions': 0.09; 'references,': 0.09; 'spelled': 0.09; 'subject:module': 0.09; 'language.': 0.14; 'aiming': 0.16; 'expressions,': 0.16; 'fuzzy': 0.16; 'intersection': 0.16; 'wrote:': 0.18; "python's": 0.19; 'header:User-Agent:1': 0.23; 'subject:problem': 0.24; 'decide': 0.24; '(see': 0.26; 'purposes': 0.26; 'header:In-Reply-To:1': 0.27; 'matching': 0.30; 'url:wiki': 0.31; 'names.': 0.31; 'sets.': 0.31; 'url:wikipedia': 0.31; 'probably': 0.32; 'supposed': 0.32; 'regular': 0.32; 'another': 0.32; 'test': 0.35; 'but': 0.35; 'there': 0.35; 'really': 0.36; 'module.': 0.36; 'similar': 0.36; 'url:org': 0.36; 'two': 0.37; 'represent': 0.38; 'to:addr:python-list': 0.38; 'rather': 0.38; 'to:addr:python.org': 0.39; 'even': 0.60; 'algorithms': 0.60; 'truly': 0.60; 'url:about': 0.61; 'back': 0.62; 'more': 0.64; 'mail.': 0.69; 'received:109': 0.72; 'received:btcentralplus.com': 0.84 User-Agent: Kaiten Mail In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: Python's re module and genealogy problem From: Simon Ward Date: Wed, 11 Jun 2014 18:21:26 +0100 To: python-list@python.org X-Spam-Flag: NO X-Spam-Score: -2.9 X-Spam-Level: -- X-Spam-Report: No, score=-2.9 required=5.0 tests=ALL_TRUSTED, BAYES_00 autolearn=ham version=3.3.2 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: 28 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1402508398 news.xs4all.nl 2966 [2001:888:2000:d::a6]:39820 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:73183 On 11 June 2014 13:23:14 BST, BrJohan wrote: >For some genealogical purposes I consider using Python's re module. > >Rather many names can be spelled in a number of similar ways, and in >order to match names even if they are spelled differently, I will build > >regular expressions, each of which is supposed to match a number of >similar names. As has been mentioned, you probably want to look at fuzzy matching algorithms rather than aiming at regular expressions, although a quick search suggests there has been some work on fuzzy matching with regular expressions[1]. >Now, my problem: Is there a way to decide whether any two - or more - >of >those regular expressions will match the same string? If your regexes are truly regular expressions (see [2]*) then they represent regular languages[3], which are really sets. The intersection of these, is another regular language. If you test the string against this it will also match both original languages. (*this only mentions back references, but I think the look-ahead/behind assertions are also non-regular) [1]: http://laurikari.net/tre/about/ [2]: https://en.wikipedia.org/wiki/Regular_expression#Patterns_for_non-regular_languages [3]: https://en.wikipedia.org/wiki/Regular_language Simon -- Sent from Kaiten Mail. Please excuse my brevity.