Re: Encoding NaN in JSON
On Sat, 20 Apr 2013, Chris “Kwpolska” Warrick wrote:
On Fri, Apr 19, 2013 at 9:42 PM, Grant Edwards invalid@invalid.invalid wrote:
The OP asked for a string, and I thought you were proposing the string
'null'. If one is to use a string, then 'NaN' makes the most sense,
since it can be converted back into a floating point NaN object.
I infer that you were proposing a JSON null value and not the string
'null'?
Not me, Wayne Werner proposed to use the JSON null value. I parsed
the backticks (`) used by him as a way to delimit it from text and not
as a string.
That was, in fact, my intention. Though it seems to me that you'll have to
suffer between some sort of ambiguity - in Chrome, at least,
`Number(null)` evaluates to `0` instead of NaN. But `Number('Whatever')`
evaluates to NaN. However, a JSON parser obviously wouldn't be able to
make the semantic distinction, so I think you'll be left with whichever
API makes the most sense to you:
NaN maps to null
or
NaN maps to NaN (or any other string, really)
Obviously you're not limited to these particular choices, but they're
probably the easiest to implement and communicate.
HTH,
-W--
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Re: Encoding NaN in JSON
On Fri, Apr 19, 2013 at 9:42 PM, Grant Edwards invalid@invalid.invalid wrote: The OP asked for a string, and I thought you were proposing the string 'null'. If one is to use a string, then 'NaN' makes the most sense, since it can be converted back into a floating point NaN object. I infer that you were proposing a JSON null value and not the string 'null'? Not me, Wayne Werner proposed to use the JSON null value. I parsed the backticks (`) used by him as a way to delimit it from text and not as a string. PS. On 2013-04-19, Chris ???Kwpolska??? Warrick kwpol...@gmail.com wrote: Is Unicode support so hard, especially in the 21st century? -- Kwpolska http://kwpolska.tk | GPG KEY: 5EAAEA16 stop html mail| always bottom-post http://asciiribbon.org| http://caliburn.nl/topposting.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
On 2013-04-19 10:34, Tim Roberts wrote:
Miki Tebeka miki.teb...@gmail.com wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
You understand that this will result in a chunk of text that is not JSON?
Other JSON readers won't be able to read it.
I think he means something like this:
json.dumps([float('nan')])
'[N/A]'
Not
'[N/A]'
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Re: Encoding NaN in JSON
On 2013-04-18, Wayne Werner wa...@waynewerner.com wrote:
On Wed, 17 Apr 2013, Miki Tebeka wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Why not use `null` instead? It seems to be semantically more similar...
Why not use 'NaN' instead? It seems to be even more semantically
similar...
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Re: Encoding NaN in JSON
On Fri, Apr 19, 2013 at 4:54 PM, Grant Edwards invalid@invalid.invalid wrote:
On 2013-04-18, Wayne Werner wa...@waynewerner.com wrote:
On Wed, 17 Apr 2013, Miki Tebeka wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Why not use `null` instead? It seems to be semantically more similar...
Why not use 'NaN' instead? It seems to be even more semantically
similar...
Because there is no NaN in JSON? Unless you mean a string, which
makes no semantical sense and is human-oriented and not
machine-oriented.
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Re: Encoding NaN in JSON
On 2013-04-19, Chris ???Kwpolska??? Warrick kwpol...@gmail.com wrote:
On Fri, Apr 19, 2013 at 4:54 PM, Grant Edwards invalid@invalid.invalid
wrote:
On 2013-04-18, Wayne Werner wa...@waynewerner.com wrote:
On Wed, 17 Apr 2013, Miki Tebeka wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of
the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Why not use `null` instead? It seems to be semantically more similar...
Why not use 'NaN' instead? It seems to be even more semantically
similar...
Because there is no NaN in JSON? Unless you mean a string, which
makes no semantical sense and is human-oriented and not
machine-oriented.
The OP asked for a string, and I thought you were proposing the string
'null'. If one is to use a string, then 'NaN' makes the most sense,
since it can be converted back into a floating point NaN object.
I infer that you were proposing a JSON null value and not the string
'null'?
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at message from EUBIE BLAKE!!
gmail.com
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Re: Encoding NaN in JSON
You understand that this will result in a chunk of text that is not JSON?
I think he means something like this:
json.dumps([float('nan')])
'[N/A]'
That's exactly what I mean :)
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Re: Encoding NaN in JSON
On Thu, Apr 18, 2013 at 11:46:37AM +1000, Chris Angelico wrote: Wait... you can do that? It's internal to iterencode, at least in Python 3.3 and 2.7 that I'm looking at here. In Python 2.6 it wasn't internal to iterencode; in Python 2.7 and 3.x you probably would have to monkey-patch iterencode. (In addition, patching floatstr alone wouldn't be enough in 3.x and probably 2.7, since you also have to make sure that the C-extension is not used here.) BUT: Keep in mind that monkey-patches are problematic, and should be avoided (or used very carefully) in production code. So, better replace the complete encoder.py or use your own patched version of the complete json-module. Roland -- http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
On Wed, 17 Apr 2013, Miki Tebeka wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Why not use `null` instead? It seems to be semantically more similar...
-W
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Re: Encoding NaN in JSON
Miki Tebeka miki.teb...@gmail.com wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
You understand that this will result in a chunk of text that is not JSON?
Other JSON readers won't be able to read it.
--
Tim Roberts, t...@probo.com
Providenza Boekelheide, Inc.
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Re: Encoding NaN in JSON
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
In c37a3b9c-6fe8-48aa-b703-9b4f922c3...@googlegroups.com Miki Tebeka
miki.teb...@gmail.com writes:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
import math
x = possibly_NaN()
if math.isnan(x):
x = 'N/A'
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Re: Encoding NaN in JSON
Miki Tebeka miki.teb...@gmail.com writes:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Easiest way is probably to transform your object before you try to write
it, e.g.
def transform(x):
if isinstance(x, dict):
return dict((k, transform(v)) for k, v in x.items())
elif isinstance(x, list) or isinstance(x, tuple):
return [transform(v) for v in x]
elif isinstance(x, float) and x != x:
return 'N/A'
else:
return x
Then just use
json.dumps(transform(x))
rather than just
json.dumps(x)
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Re: Encoding NaN in JSON
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
Easiest way is probably to transform your object before you try to write
Yeah, that's what I ended up doing. Wondered if there's a better way ...
Thanks,
--
Miki
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Re: Encoding NaN in JSON
On 04/17/2013 03:05 PM, Johann Hibschman wrote:
Miki Tebeka miki.teb...@gmail.com writes:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
No. There is no way to represent NaN in JSON. It's simply not part of the
specification.
I know that. I'm trying to emit the *string* 'N/A' for every NaN.
Easiest way is probably to transform your object before you try to write
it, e.g.
def transform(x):
if isinstance(x, dict):
return dict((k, transform(v)) for k, v in x.items())
elif isinstance(x, list) or isinstance(x, tuple):
return [transform(v) for v in x]
elif isinstance(x, float) and x != x:
return 'N/A'
else:
return x
Note that for a self-referencing object, this function might run
forever, or until it runs out of stack. The programmer is likely to
know about the possibility, but just in case ...
Then just use
json.dumps(transform(x))
rather than just
json.dumps(x)
--
DaveA
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Re: Encoding NaN in JSON
Hi, Easiest way is probably to transform your object before you try to write Yeah, that's what I ended up doing. Wondered if there's a better way ... yes, there is: subclass+extend the JSON-encoder, see pydoc json. e.g.: class JsonNanEncoder(json.JSONEncoder): def default(self, obj): if some-check-if-obj-is-NaN: return 'NaN' return json.JSONEncoder.default(self, obj) Roland -- http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
[Roland] 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. -- http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
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
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Re: Encoding NaN in JSON
On Thu, Apr 18, 2013 at 11:01 AM, Miki Tebeka miki.teb...@gmail.com wrote: [Roland] 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. You may be able to override a bit more of the code, though. Check out Lib/json/encoder.py for the implementation, and have a look at the floatstr() internal function; unfortunately you can't simply subclass and override that, but perhaps overriding iterencode (which is where floatstr is defined) would do the job. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Encoding NaN in JSON
On Thu, Apr 18, 2013 at 11:39 AM, Roland Koebler r.koeb...@yahoo.de wrote: 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.) Wait... you can do that? It's internal to iterencode, at least in Python 3.3 and 2.7 that I'm looking at here. Can you share your code please? I'd like to try that! When I first looked at the docstring, I was thinking Ah, can I override the bit that emits NaN to return \N/A\ instead?, but the code made me think that's not possible. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Encoding NaN in JSON
Greetings,
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
I can't seem to find a way since NaN is a float, which means overriding
default won't help.
Any simple way to do this?
Thanks,
--
Miki
--
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Re: Encoding NaN in JSON
Miki Tebeka miki.teb...@gmail.com wrote:
I'm trying to find a way to have json emit float('NaN') as 'N/A'.
I can't seem to find a way since NaN is a float, which means overriding
default won't help.
Any simple way to do this?
No. There is no way to represent NaN in JSON. It's simply not part of the
specification. From RFC 4627 section 2.4:
Numeric values that cannot be represented as sequences of digits
(such as Infinity and NaN) are not permitted.
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Providenza Boekelheide, Inc.
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