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

Groups > comp.lang.python > #37061

Re: Safely add a key to a dict only if it does not already exist?

Path csiph.com!usenet.pasdenom.info!news.albasani.net!newsfeed.freenet.ag!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!194.109.133.83.MISMATCH!newsfeed.xs4all.nl!newsfeed4.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path <python-python-list@m.gmane.org>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.003
X-Spam-Evidence '*H*': 0.99; '*S*': 0.00; 'received:151': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'sure,': 0.09; 'subject:not': 0.11; 'received:80.91.229.3': 0.16; 'received:net24.it': 0.16; 'received:plane.gmane.org': 0.16; 'setdefault': 0.16; 'subject:already': 0.16; 'subject:key': 0.16; 'thread-safe': 0.16; 'wrote:': 0.17; 'element': 0.17; 'header :User-Agent:1': 0.26; 'header:X-Complaints-To:1': 0.28; 'chris': 0.28; "i'm": 0.29; 'sense': 0.31; 'to:addr:python-list': 0.33; 'subject:?': 0.35; 'add': 0.36; 'received:org': 0.36; 'but': 0.36; 'subject:: ': 0.38; 'to:addr:python.org': 0.39; 'header:Received:5': 0.40; 'dict,': 0.84; 'investigated': 0.84; 'subject:add': 0.91
X-Injected-Via-Gmane http://gmane.org/
To python-list@python.org
From Vito De Tullio <vito.detullio@gmail.com>
Subject Re: Safely add a key to a dict only if it does not already exist?
Date Sat, 19 Jan 2013 08:27:12 +0100
References <50fa1bf1$0$30003$c3e8da3$5496439d@news.astraweb.com> <CAMZYqRT9SkzNh2BDC1cccCGsbjHw_jWJ-m+DTuc8NwtfAsmRpg@mail.gmail.com>
Mime-Version 1.0
Content-Type text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding 7Bit
X-Gmane-NNTP-Posting-Host adsl-ull-55-244.45-151.net24.it
User-Agent KNode/4.9.4
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.15
Precedence list
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>
Newsgroups comp.lang.python
Message-ID <mailman.672.1358580589.2939.python-list@python.org> (permalink)
Lines 12
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1358580589 news.xs4all.nl 6959 [2001:888:2000:d::a6]:38419
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:37061

Show key headers only | View raw

Chris Rebert wrote:

>> How can I add a key in a thread-safe manner?
> I'm not entirely sure, but have you investigated dict.setdefault() ?

but how setdefault makes sense in this context? It's used to set a default 
value when you try to retrieve an element from the dict, not when you try to 
set a new one ...

-- 
ZeD

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

Thread

Safely add a key to a dict only if it does not already exist? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-19 04:07 +0000
  Re: Safely add a key to a dict only if it does not already exist? Chris Rebert <clp2@rebertia.com> - 2013-01-18 20:15 -0800
    Re: Safely add a key to a dict only if it does not already exist? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-19 10:31 +0000
  Re: Safely add a key to a dict only if it does not already exist? Lie Ryan <lie.1296@gmail.com> - 2013-01-19 16:00 +1100
  Re: Safely add a key to a dict only if it does not already exist? Vito De Tullio <vito.detullio@gmail.com> - 2013-01-19 08:25 +0100
  Re: Safely add a key to a dict only if it does not already exist? Vito De Tullio <vito.detullio@gmail.com> - 2013-01-19 08:27 +0100
  Re: Safely add a key to a dict only if it does not already exist? Mitya Sirenef <msirenef@lightbird.net> - 2013-01-19 02:35 -0500
  Re: Safely add a key to a dict only if it does not already exist? Peter Otten <__peter__@web.de> - 2013-01-19 09:02 +0100
  Re: Safely add a key to a dict only if it does not already exist? Vito De Tullio <vito.detullio@gmail.com> - 2013-01-19 09:16 +0100
  Re: Safely add a key to a dict only if it does not already exist? Mitya Sirenef <msirenef@lightbird.net> - 2013-01-19 03:18 -0500
  Re: Safely add a key to a dict only if it does not already exist? Vito De Tullio <vito.detullio@gmail.com> - 2013-01-19 09:19 +0100
  Re: Safely add a key to a dict only if it does not already exist? Chris Angelico <rosuav@gmail.com> - 2013-01-19 19:23 +1100
  Re: Safely add a key to a dict only if it does not already exist? Roy Smith <roy@panix.com> - 2013-01-19 08:04 -0500

csiph-web