Path: csiph.com!usenet.pasdenom.info!news.albasani.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed2a.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 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'from:addr:yahoo.co.uk': 0.04; 'resulting': 0.04; 'output': 0.05; 'keys,': 0.09; 'lawrence': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'language.': 0.14; 'changes': 0.15; 'dict': 0.16; 'happy,': 0.16; 'intersection': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'subject:dictionaries': 0.16; 'language': 0.16; 'wrote:': 0.18; 'code,': 0.22; 'example': 0.22; 'tests': 0.22; 'header:User-Agent:1': 0.23; '---': 0.24; "i've": 0.25; 'defined': 0.27; 'header:X-Complaints-To:1': 0.27; 'header :In-Reply-To:1': 0.27; 'patch': 0.29; 'raise': 0.29; '???': 0.30; 'lot.': 0.31; 'probably': 0.32; 'case,': 0.35; 'operations': 0.35; 'but': 0.35; 'should': 0.36; 'to:addr:python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'everybody': 0.60; 'most': 0.60; 'free': 0.61; 'viruses': 0.61; 'complete': 0.62; 'protection': 0.63; 'our': 0.64; 'here': 0.66; 'antivirus': 0.68; 'obvious': 0.74; 'choice.': 0.93; 'enhancement': 0.95 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Mark Lawrence Subject: Re: intersection, union, difference, symmetric difference for dictionaries Date: Tue, 25 Feb 2014 22:35:00 +0000 References: <%x8Pu.24267$Th2.3261@tornado.fastwebnet.it> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Gmane-NNTP-Posting-Host: host-78-147-191-107.as13285.net User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 In-Reply-To: <%x8Pu.24267$Th2.3261@tornado.fastwebnet.it> X-Antivirus: avast! (VPS 140225-1, 25/02/2014), Outbound message X-Antivirus-Status: Clean 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: 41 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1393367696 news.xs4all.nl 2944 [2001:888:2000:d::a6]:43471 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:67070 On 25/02/2014 22:11, mauro wrote: > >> >> {1, 2} & {2, 3} == {2} >> > In my mind the intersection is evaluated on keys, so the resulting dict > should be the empty one >> but >> >> {1:"a", 2:"b", 3:"c"} & {2:"b", 3:"e", 4:"f"} == ??? > my output will be > {2:"b", 3:"e"} > or > {2:"b", 3:"c"} > > depending on the implementation choice. >> >> The most obvious result is probably the empty dict {2:"b"}, i. e. >> >> a & b is defined as dict(a.items() & b.items()) >> >> Frankly, I don't do that a lot. So what's your use-case? > I do not have an use case, but I've seen that many people ask for these > operations for example in stackoverflow.com > Please ask one of the many people on stackoverflow to raise an enhancement request here bugs.python.org complete with a patch that changes code, docs and tests and then everybody will be happy, won't they. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com