Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.freenet.ag!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path: <r.koebler@yahoo.de>
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; 'true,': 0.05; 'encoded': 0.07; 'float': 0.07; 'json': 0.07; 'encode': 0.09; 'wrapper': 0.09; 'suggest': 0.14; '"n/a"': 0.16; '-infinity': 0.16; 'compliant,': 0.16; 'encoders': 0.16; 'from:addr:r.koebler': 0.16; 'from:name:roland koebler': 0.16; 'infinity,': 0.16; 'json:': 0.16; 'nan': 0.16; 'received:78.47': 0.16; 'valueerror': 0.16; '>>>': 0.22; 'import': 0.22; 'otherwise,': 0.22; '(see': 0.26; 'suggested': 0.26; 'post': 0.26; 'header:In-Reply-To:1': 0.27; 'patch': 0.29; 'such.': 0.31; 'extend': 0.32; 'quite': 0.32; 'could': 0.34; 'but': 0.35; 'there': 0.35; 'consistent': 0.36; 'module.': 0.36; 'skip:j 20': 0.36; 'charset:us-ascii': 0.36; 'hi,': 0.36; 'to:addr:python-list': 0.38; 'does': 0.39; 'to:addr:python.org': 0.39; 'even': 0.60; 'read': 0.60; 'most': 0.60; 'simply': 0.61; 'simple': 0.61; 'content- disposition:inline': 0.62; 'such': 0.63; 'default': 0.69; 'behavior': 0.77
Date: Thu, 18 Apr 2013 03:39:38 +0200
From: Roland Koebler <r.koebler@yahoo.de>
To: python-list@python.org
Subject: Re: Encoding NaN in JSON
References: <20130417224030.GA28906@localhost> <1040891b-d350-4304-8112-de4a383562dc@googlegroups.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1040891b-d350-4304-8112-de4a383562dc@googlegroups.com>
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.746.1366249181.3114.python-list@python.org>
Lines: 26
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1366249181 news.xs4all.nl 2195 [2001:888:2000:d::a6]:59103
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:43795

Hi,

> > yes, there is: subclass+extend the JSON-encoder, see pydoc json.
> Please read the original post before answering. What you suggested does not work since NaN is of float type.
ok, right, default does not work this way.
But I would still suggest to extend the JSON-encoder, since that is
quite simple (see sourcecode of JSON module); as a quickhack, you
could even monkey patch json.encoder.floatstr with a wrapper which
returns "N/A" for NaN. (I've tested it: It works.)

But: If you only need NaN and inf, and are ok with 'NaN' instead of 'N/A',
you can simply use the json module. See pydoc json:

    If allow_nan is True, then NaN, Infinity, and -Infinity will be
    encoded as such.  This behavior is not JSON specification compliant,
    but is consistent with most JavaScript based encoders and decoders.
    Otherwise, it will be a ValueError to encode such floats.

>>> import json
>>> json.dumps(float('NaN'))
'NaN'
>>> json.dumps(float('inf'))
'Infinity'


Roland