Serializing a Python namedtuple to json

python json namedtuple
calvinkrishy picture calvinkrishy · May 6, 2011 · Viewed 46.7k times · Source

What is the recommended way of serializing a namedtuple to json with the field names retained?

Serializing a namedtuple to json results in only the values being serialized and the field names being lost in translation. I would like the fields also to be retained when json-ized and hence did the following:

class foobar(namedtuple('f', 'foo, bar')):
    __slots__ = ()
    def __iter__(self):
        yield self._asdict()

The above serializes to json as I expect and behaves as namedtuple in other places I use (attribute access etc.,) except with a non-tuple like results while iterating it (which fine for my use case).

What is the "correct way" of converting to json with the field names retained?

Answer

benselme picture benselme · Apr 4, 2013

If it's just one namedtuple you're looking to serialize, using its _asdict() method will work (with Python >= 2.7)

>>> from collections import namedtuple
>>> import json
>>> FB = namedtuple("FB", ("foo", "bar"))
>>> fb = FB(123, 456)
>>> json.dumps(fb._asdict())
'{"foo": 123, "bar": 456}'

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