Demonstrate how to loads/dumps json with float value as decimal.Decimal in Python

test_json_decimal.py

import json
import decimal
import pprint

# refs: https://djangosnippets.org/snippets/2410/
# refs: http://stackoverflow.com/questions/1960516/python-json-serialize-a-decimal-object
class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, decimal.Decimal):
            return float(obj)
        return json.JSONEncoder.default(self, obj)


a = {'decimal': decimal.Decimal('3.14')}

try:
    print("failed to dumps {}".format(repr(a)))
    pprint.pprint(json.dumps(a))
except Exception as ex:
    print(ex)

# Output has one decimal, change format if you need more
json.encoder.FLOAT_REPR = lambda o: format(o, '.1f')
print("successfully dumps {}".format(repr(a)))
pprint.pprint(json.dumps(a, cls=DecimalEncoder))

b = '{"decimal": 3.14}'
print("successfully loads {}".format(repr(b)))
pprint.pprint(json.loads(b, parse_float=decimal.Decimal))