Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!selfless.tophat.at!newsfeed.xs4all.nl!newsfeed6.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; 'value,': 0.04; 'mrab': 0.05; '21,': 0.09; 'hash': 0.09; 'integer,': 0.09; 'am,': 0.14; 'received:209.85.214.174': 0.14; 'received:mail- iw0-f174.google.com': 0.14; 'wrote:': 0.14; '(is': 0.16; 'angelico': 0.16; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'header:In-Reply-To:1': 0.21; 'objects,': 0.23; 'objects': 0.23; 'index': 0.25; 'stored': 0.25; 'message- id:@mail.gmail.com': 0.28; 'received:209.85.214': 0.28; 'sat,': 0.29; 'elements': 0.29; 'array': 0.30; 'looks': 0.31; 'to:addr :python-list': 0.33; 'it?': 0.33; 'chris': 0.34; 'there': 0.35; 'identical': 0.35; 'received:google.com': 0.37; 'received:209.85': 0.37; 'two': 0.37; 'could': 0.38; 'but': 0.38; 'subject:: ': 0.38; 'received:209': 0.39; 'to:addr:python.org': 0.39; 'spell': 0.91 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=JLiLuG3H5ZvtfXQDk2bwI9Sak0A7dbFQWrxKfAf1WyM=; b=awa8Nqfv5fPMvY4L9S6YvIA6a1rDOyVKPACemaB2pqDg4B256M44Zp4PCCdiLkw/e0 TJAtoVVVliVmc6SZxSTiJfJeXSMXbWNj06rpVdfYy8YVIU5KPvB2ESlnwenBIdKuS+kA 5C1A5q3HOw8H+1xRXMnf6xL9bmh4Np2RpKMiU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=k44qlS30t21WSboRHiMd9FD6TqeKf0Y2XzHWn4vztOlwsmhaSnuv1zTRJ07RV4PyCN du4tD5Ufpie6/6IhqE4mkwOLkA53Ip18Jy/6kPUmxJJZuXVhKYitnI2VRERCjOPxAK5G FNfCMmHifJ8G+WG9X/wyy8wbBQEhzMdaIj0f4= MIME-Version: 1.0 In-Reply-To: <4DD68DAA.9050209@mrabarnett.plus.com> References: <4DD2C2A5.3080403@stoneleaf.us> <4DD2D89D.4000303@stoneleaf.us> <4DD2F661.2050005@stoneleaf.us> <0deha8-6u9.ln1@satorlaser.homedns.org> <4DD68DAA.9050209@mrabarnett.plus.com> Date: Sat, 21 May 2011 02:20:04 +1000 Subject: Re: hash values and equality From: Chris Angelico To: python-list@python.org Content-Type: text/plain; charset=ISO-8859-1 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: 12 NNTP-Posting-Host: 82.94.164.166 X-Trace: 1305908408 news.xs4all.nl 49184 [::ffff:82.94.164.166]:58001 X-Complaints-To: abuse@xs4all.nl Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:5857 On Sat, May 21, 2011 at 1:50 AM, MRAB wrote: > [snip] > Is this strictly true? I thought that the hash value, an integer, is > moduloed (Is that how you spell it? Looks weird!) with the number of > array elements to give an index into the array, so different hashes > could give the same index, and objects with different hashes could be > stored in the same 'bucket'. There can always be hash collisions between different objects, but the assumption is that two identical objects will _always_ "collide". Chris Angelico