Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #16767

Re: order independent hash?

Path csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path <dihedral88888@googlemail.com>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.017
X-Spam-Evidence '*H*': 0.97; '*S*': 0.00; 'bug': 0.02; 'function,': 0.07; 'python': 0.08; 'compute': 0.09; 'reply- to:addr:comp.lang.python': 0.09; 'to:addr:comp.lang.python': 0.09; 'tuple': 0.09; 'algorithm': 0.13; 'stored': 0.13; 'non-trivial': 0.16; 'subject:independent': 0.16; 'cc:addr:python-list': 0.16; 'meant': 0.17; 'wrote:': 0.18; 'position,': 0.19; "haven't": 0.20; 'memory': 0.21; 'dec': 0.22; 'header:In-Reply-To:1': 0.22; 'dictionary': 0.23; 'pair': 0.23; 'table.': 0.23; 'cc:2**0': 0.24; "python's": 0.24; 'stack': 0.24; 'function': 0.27; 'received:209.85.220': 0.27; 'work.': 0.28; 'cc:addr:python.org': 0.29; 'pm,': 0.29; 'hash': 0.30; 'objects.': 0.30; 'oop': 0.30; 'sun,': 0.30; 'subject:?': 0.31; 'objects': 0.32; 'idea': 0.32; 'header:User-Agent:1': 0.33; 'this.': 0.33; 'done': 0.34; 'from:addr:googlemail.com': 0.34; 'too': 0.34; 'all.': 0.34; 'avoiding': 0.34; 'then.': 0.34; 'list.': 0.35; 'something': 0.35; 'sets': 0.35; 'explain': 0.36; 'received:google.com': 0.37; 'think': 0.37; 'linked': 0.38; 'maps': 0.38; 'monday,': 0.38; 'some': 0.38; 'received:209.85': 0.38; 'tables': 0.39; 'why': 0.39; 'called': 0.40; 'received:209': 0.40; 'management': 0.60; 'type': 0.61; '2011': 0.61; 'miss': 0.62; 'leading': 0.62; 'power': 0.63; 'stated': 0.68; 'header:Reply-To:1': 0.71; 'reply- to:no real name:2**0': 0.72; 'time?': 0.73; 'reply- to:addr:googlegroups.com': 0.74; 'free?': 0.84; 'sets,': 0.84; 'shrinking': 0.84; '\xa0there': 0.91
Newsgroups comp.lang.python
Date Tue, 6 Dec 2011 21:24:42 -0800 (PST)
In-Reply-To <mailman.3281.1323041121.27778.python-list@python.org>
Complaints-To groups-abuse@google.com
Injection-Info glegroupsg2000goo.googlegroups.com; posting-host=1.168.138.227; posting-account=5JdMBQoAAABHnS4mjpqEzxnmWtgiiVNw
References <jb57p7$b1j$1@dough.gmane.org> <mailman.3156.1322657239.27778.python-list@python.org> <30715729.411.1322753732534.JavaMail.geo-discussion-forums@pret21> <4ED7A2CE.6070306@davea.name> <mailman.3203.1322756312.27778.python-list@python.org> <6366868.86.1322800180523.JavaMail.geo-discussion-forums@pret21> <mailman.3216.1322802013.27778.python-list@python.org> <mailman.3218.1322804917.27778.python-list@python.org> <3MKCq.194015$th7.47228@newsfe07.ams2> <26969335.380.1323013143216.JavaMail.geo-discussion-forums@prnu18> <mailman.3272.1323020507.27778.python-list@python.org> <27797359.1293.1323021983756.JavaMail.geo-discussion-forums@prfb10> <mailman.3278.1323029614.27778.python-list@python.org> <12469565.1384.1323040641935.JavaMail.geo-discussion-forums@prfj18> <mailman.3281.1323041121.27778.python-list@python.org>
User-Agent G2/1.0
X-Google-Web-Client true
MIME-Version 1.0
Subject Re: order independent hash?
From 88888 Dihedral <dihedral88888@googlemail.com>
To comp.lang.python@googlegroups.com
Content-Type text/plain; charset=ISO-8859-1
Content-Transfer-Encoding quoted-printable
Cc Python <python-list@python.org>
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.12
Precedence list
Reply-To comp.lang.python@googlegroups.com
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Message-ID <mailman.3370.1323235492.27778.python-list@python.org> (permalink)
Lines 38
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1323235492 news.xs4all.nl 6942 [2001:888:2000:d::a6]:39414
X-Complaints-To abuse@xs4all.nl
Xref x330-a1.tempe.blueboxinc.net comp.lang.python:16767

Show key headers only | View raw

On Monday, December 5, 2011 7:24:49 AM UTC+8, Ian wrote:
> On Sun, Dec 4, 2011 at 4:17 PM, 88888 Dihedral
> <dihedr...@googlemail.com> wrote:
> >> Please explain what you think a hash function is, then.  Per
> >> Wikipedia, "A hash function is any algorithm or subroutine that maps
> >> large data sets to smaller data sets, called keys."
> >>
> >> > Are you miss-leading the power of true OOP ?
> >>
> >> I have no idea what you are suggesting.  I was not talking about OOP at all.
> >
> > In python the (k,v) pair in a dictionary k and v can be  both an objects.
> > v can be a tuple or a list.  There are some restrictions on k to be an
> >  hashable type in python's implementation. The key is used to compute the position of the pair to be stored in a  hash table. The hash function maps key k to the position in the hash table. If k1!=k2 are both  mapped to the same
> > position, then something has to be done to resolve this.
> 
> I understand how dicts / hash tables work.  I don't need you to
> explain that to me.  What you haven't explained is why you stated that
> a hash function that operates on objects is not a hash function, or
> what you meant by "misleading the power of true OOP".

Do you  forget the memory management of a dictionary in Python that has 
to be linked for a dynamical growing and shrinking number of (k,v) pairs 
in a long period of time?

Avoiding the true non-trivial part in any implementation or use of a dictionary  is miss leading ? 

Probing too deep in the stack or occupying too much in the heap is not
bug free?

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: order independent hash? Peter Otten <__peter__@web.de> - 2011-11-30 13:47 +0100
  Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 07:35 -0800
  Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 07:35 -0800
    Re: order independent hash? Dave Angel <d@davea.name> - 2011-12-01 10:52 -0500
      Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 08:17 -0800
      Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 08:17 -0800
    Re: order independent hash? Chris Angelico <rosuav@gmail.com> - 2011-12-02 03:18 +1100
      Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 20:29 -0800
        Re: order independent hash? Chris Angelico <rosuav@gmail.com> - 2011-12-02 16:00 +1100
          Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 21:48 -0800
            Re: order independent hash? Lie Ryan <lie.1296@gmail.com> - 2011-12-05 00:40 +1100
          Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 21:48 -0800
            Re: order independent hash? Roel Schroeven <rschroev_nospam_ml@fastmail.fm> - 2011-12-04 14:41 +0100
              Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 07:39 -0800
                Re: order independent hash? Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-04 10:41 -0700
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 10:06 -0800
                Re: order independent hash? Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-04 13:13 -0700
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 15:17 -0800
                Re: order independent hash? Matt Joiner <anacrolix@gmail.com> - 2011-12-05 10:21 +1100
                Re: order independent hash? Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-04 16:24 -0700
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 16:52 -0800
                Re: order independent hash? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-05 02:00 +0000
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 16:52 -0800
                Re: order independent hash? Lie Ryan <lie.1296@gmail.com> - 2011-12-05 12:59 +1100
                Re: order independent hash? Ethan Furman <ethan@stoneleaf.us> - 2011-12-04 18:08 -0800
                Re: order independent hash? Ben Finney <ben+python@benfinney.id.au> - 2011-12-05 15:52 +1100
                Re: order independent hash? Matt Joiner <anacrolix@gmail.com> - 2011-12-05 14:02 +1100
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-06 21:24 -0800
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-06 21:24 -0800
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 15:17 -0800
                Re: order independent hash? Terry Reedy <tjreedy@udel.edu> - 2011-12-04 19:28 -0500
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-04 10:06 -0800
          Re: order independent hash? Hrvoje Niksic <hniksic@xemacs.org> - 2011-12-02 10:53 +0100
            Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-02 03:48 -0800
            Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-02 09:00 -0800
            Re: order independent hash? Terry Reedy <tjreedy@udel.edu> - 2011-12-02 16:40 -0500
              Re: order independent hash? Hrvoje Niksic <hniksic@xemacs.org> - 2011-12-04 14:55 +0100
                Re: order independent hash? Chris Angelico <rosuav@gmail.com> - 2011-12-05 01:08 +1100
                Re: order independent hash? Hrvoje Niksic <hniksic@xemacs.org> - 2011-12-07 14:28 +0100
                Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-07 09:48 -0800
                Re: order independent hash? Tim Chase <python.list@tim.thechases.com> - 2011-12-04 12:57 -0600
                Re: order independent hash? Hrvoje Niksic <hniksic@xemacs.org> - 2011-12-08 10:30 +0100
                Re: order independent hash? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-09 11:27 +0000
                Re: order independent hash? Hrvoje Niksic <hniksic@xemacs.org> - 2011-12-09 17:51 +0100
                Re: order independent hash? Chris Angelico <rosuav@gmail.com> - 2011-12-10 04:13 +1100
                Re: order independent hash? Lie Ryan <lie.1296@gmail.com> - 2011-12-11 10:58 +1100
                Re: order independent hash? Chris Angelico <rosuav@gmail.com> - 2011-12-11 11:17 +1100
                Re: order independent hash? Lie Ryan <lie.1296@gmail.com> - 2011-12-11 14:04 +1100
        Re: order independent hash? Lie Ryan <lie.1296@gmail.com> - 2011-12-05 00:29 +1100
      Re: order independent hash? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-01 20:29 -0800
      Re: order independent hash? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-02 04:33 +0000

csiph-web