Re: Looking up a dictionary _key_ by key?

From	Laura Creighton <lac@openend.se>
Subject	Re: Looking up a dictionary _key_ by key?
References	<CAGGBd_pd9SA7SczanGARFr-+Z9SxP9Mkhfo-RivpcJLrnuexng@mail.gmail.com> <851th2t05t.fsf@benfinney.id.au> <CAGGBd_qaNC38Yg0u_b8+qBAckq6FRTZMxbWwuzV=MUYE_=ZzDw@mail.gmail.com> <mailman.3.1435107726.3674.python-list@python.org><87a8vpykwq.fsf@nightsong.com>
Date	2015-07-05 08:25 +0200
Newsgroups	comp.lang.python
Message-ID	<mailman.301.1436077546.3674.python-list@python.org> (permalink)

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In a message of Tue, 23 Jun 2015 18:06:45 -0700, Paul Rubin writes:
>Chris Angelico <rosuav@gmail.com> writes:
>>> Would I have to do an O(n) search to find my key?
>> Iterate over it - it's an iterable view in Py3 - and compare.
>
>I think the question was whether the O(n) search could be avoided, not
>how to do it.  I don't see a way to avoid it.  There is fundamental
>brokenness in having unequal objects compare as equal, and the breakage
>messes up the dictionary when those objects are used as keys.
>
>Solution is to either fix the object equality test, or wrap them in
>something (maybe a tuple containing the objects and the distinguishing
>fields that are missing from the original object's equality method) that
>treats unequal objects as unequal.
>-- 
>https://mail.python.org/mailman/listinfo/python-list

This just showed up in my mailbox:

     Subject: [ANN] pyskiplist-1.0.0
     From:    Geert Jansen <geertj@gmail.com>

     PySkipList is a fast, pure Python implementation of an indexable
     skiplist. It implements a SkipList data structure that provides an
     always sorted, list-like data structure for (key, value) pairs.

... more details including timing.  For the full text see
https://github.com/geertj/pyskiplist
It's also available on PyPI.

Looks to me as if he's fixed the 0(n) problem ....

Laura

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Re: Looking up a dictionary _key_ by key? Chris Angelico <rosuav@gmail.com> - 2015-06-24 11:02 +1000
  Re: Looking up a dictionary _key_ by key? Paul Rubin <no.email@nospam.invalid> - 2015-06-23 18:06 -0700
    Re: Looking up a dictionary _key_ by key? Ian Kelly <ian.g.kelly@gmail.com> - 2015-06-24 00:50 -0600
      Re: Looking up a dictionary _key_ by key? Marko Rauhamaa <marko@pacujo.net> - 2015-06-24 09:55 +0300
    Re: Looking up a dictionary _key_ by key? Laura Creighton <lac@openend.se> - 2015-07-05 08:25 +0200

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