Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder2.enfer-du-nord.net!newsfeed.eweka.nl!eweka.nl!feeder3.eweka.nl!newsfeed.xs4all.nl!newsfeed6.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 0.053 X-Spam-Evidence: '*H*': 0.89; '*S*': 0.00; 'compute': 0.09; 'def': 0.13; 'cache': 0.15; 'block,': 0.16; 'name),': 0.16; 'subject:function': 0.16; 'to:addr:pearwood.info': 0.16; 'to:addr:steve+comp.lang.python': 0.16; "to:name:steven d'aprano": 0.16; 'cc:addr:python-list': 0.16; "wouldn't": 0.17; 'wrote:': 0.18; 'convert': 0.19; 'cc:no real name:2**0': 0.20; 'header:In- Reply-To:1': 0.22; 'cc:2**0': 0.24; 'code.': 0.26; 'function': 0.27; "wasn't": 0.28; 'bit': 0.28; 'explicit': 0.29; 'looks': 0.29; 'cc:addr:python.org': 0.29; 'pm,': 0.29; 'class': 0.29; 'that...': 0.30; 'useless': 0.30; 'actual': 0.32; 'idea': 0.32; 'received:209.85.161.46': 0.32; 'received:mail- fx0-f46.google.com': 0.32; 'message-id:@gmail.com': 0.33; 'header :User-Agent:1': 0.33; 'instead': 0.33; 'object': 0.33; 'it.': 0.34; 'something': 0.35; 'received:209.85.161': 0.36; '(from': 0.37; 'but': 0.37; 'received:google.com': 0.37; 'skip:_ 10': 0.37; 'doing': 0.38; 'received:10.0.0': 0.38; 'steven': 0.38; 'received:209.85': 0.38; 'subject:from': 0.38; 'either': 0.39; "it's": 0.40; 'received:209': 0.40; 'property': 0.63; 'perfect': 0.64; 'below.': 0.66; 'natural': 0.66; 'square': 0.67; 'show': 0.67; 'design.': 0.73; '11:37': 0.84; 'canonical': 0.91; 'demand.': 0.91 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=L01HzxFtQVO32rJ5uB0rLgDPAe5UPvJO8cLWBjiUsrA=; b=Cxx7DtUQJUlYdLB/xJvTr58NSA/U0eAPXarCoA660pAbuBqsmkrx8ZZ6W+/kz0gx5/ Xl+goj+4xFkF5GK16tGYbZyXx3tvECvPZJ859f+fgkhcLuBPvOnSlJziRUuIJSodYT8V 1nhgWbte5yq+psh4XAfil6ShJQkDOQMdSYvKA= Date: Wed, 14 Dec 2011 09:42:08 +0000 From: Andrea Crotti User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111108 Thunderbird/8.0 MIME-Version: 1.0 To: Steven D'Aprano Subject: Re: boolean from a function References: <4ee7e1a4$0$29979$c3e8da3$5496439d@news.astraweb.com> In-Reply-To: <4ee7e1a4$0$29979$c3e8da3$5496439d@news.astraweb.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: python-list@python.org X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 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: 34 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1323855732 news.xs4all.nl 6848 [2001:888:2000:d::a6]:56733 X-Complaints-To: abuse@xs4all.nl Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:17188 On 12/13/2011 11:37 PM, Steven D'Aprano wrote: > > x is a global? Poor design. But in any case, instead of an explicit > if...else block, the canonical way to convert an arbitrary object to True/ > False is with bool: > > def func_bool(): > return bool(x) > > But you don't need it. See below. > > > No no it was just to show the pattern, it wasn't the actual code. I don't like to have useless indirections, so I wouldn't do that... I like the idea of the property (from Duncan Booth) but the thing is that that function looks like it's doing something (from its name), it's not just a simple property. In the case of the square class Sq(object): def __init__(self, x, y): self.x = x self.y It makes perfect sense to have "area" as a property, because you can either compute it and cache it or compute it on demand. It feels a bit less natural to create a property on something that is less simple than that imho..