Decimal to JSON [duplicate]

This question already has answers here: Python JSON serialize a Decimal object 开发者_StackOverflow社区 (21 answers) Closed 5 years ago.

I'm pulling a sum from a DB which is a decimal value. I'm trying to use that value in a JSON result

json.dumps( { 'sum': amount } ) #where amount is my Decimal

Django can't serialize the Decimal. I can convert it to a string, but I'd like a numeric type within the JSON. If I try and convert it to a float I end up with more than 2 decimal places.

What needs to happen, if possible, to get a result like the following?

{ 'sum': 500.50 }

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What you can do is extend the JSONDecoder class to provide a custom serializer for the Decimal type, similar to the example in this document: http://docs.python.org/py3k/library/json.html

>>> import json
>>> class DecimalEncoder(json.JSONEncoder):
...     def default(self, obj):
...         if isinstance(obj, Decimal):
...             return "%.2f" % obj
...         return json.JSONEncoder.default(self, obj)
...

That's a nonworking example of how to do it, hopefully a good starting point for you.

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From this link : http://code.google.com/p/simplejson/issues/detail?id=34.

i can tell you tree think :

• use cjson it work fine with decimal values.

• use monkey patching like the example from this link: http://code.google.com/p/simplejson/issues/detail?id=61

• use jsonutil see the last comment : http://code.google.com/p/simplejson/issues/detail?id=34#c28

you can find more detail in the first link.

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Decimal can be cast to a float which javascript knows how to deal with

json.dumps( { 'sum': float(amount) } )

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There's no such thing as a Decimal type in Javascript, and also among the standard types in python. It is a database-spcific type and not part of JSON. Take Float or do an integer arithmetic.