numpy booleans are not JSON serializable

[DavidAntliff]

If a numpy function that returns a numpy boolean such as np.all() is used, such as in A3Part3 where isRealEven is calculated and returned, the JSON serialization in submit.py will fail with the error:

Traceback (most recent call last):
  File "submitA3.py", line 309, in <module>
    submit()
  File "submitA3.py", line 56, in submit
    rep = submitSolution(email, password, output(partIdx), partIdx)
  File "submitA3.py", line 274, in output
    outputString += convertNpObjToStr(ans) + '\n'
  File "submitA3.py", line 209, in convertNpObjToStr
    return json.dumps(obj)
  File "/home/.../.pyenv/versions/2.7.13/lib/python2.7/json/__init__.py", line 244, in dumps
    return _default_encoder.encode(obj)
  File "/home/.../.pyenv/versions/2.7.13/lib/python2.7/json/encoder.py", line 207, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/home/.../.pyenv/versions/2.7.13/lib/python2.7/json/encoder.py", line 270, in iterencode
    return _iterencode(o, 0)
  File "/home/.../.pyenv/versions/2.7.13/lib/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: True is not JSON serializable

One workaround seems to be to convert isRealEven to a Python bool with isRealEven = bool(np.all(...)).

[csaftoiu]

this will fix it as well:

class CustomJSONEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, np.bool_):
            return super(DateTimeJSONEncoder, self).encode(bool(obj))

        return super(DateTimeJSONEncoder, self).default(obj)

And then:

json.dump(obj, f, cls=CustomJSONEncoder)

[tszwangkwong]

Where is DateTimeJSONEncoder?

[HarmC]

He renamed his class later. Everywhere where it says DateTimeJSONEncoder, it should say CustomJSONEncoder

So then it is this

class CustomJSONEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, np.bool_):
            return super(CustomJSONEncoder, self).encode(bool(obj))
        return super(CustomJSONEncoder, self).default(obj)

And then:

json.dump(obj, f, cls=CustomJSONEncoder)

works for me

full credits to csaftoiu