JSON serialization support for NumPy ndarray objects.

json_numpy.py

from functools import partial
import io
import json
import numpy as np

def as_numpy(dct):
    """JSON decoder for NumPy ndarrays."""
    if '__numpy__' in dct:
        return np.load(io.BytesIO(dct['data'].encode('latin-1')))
    return dct

class NumpyEncoder(json.JSONEncoder):
    """JSON Encoder for NumPy ndarrays."""
    def default(self, obj):
        if isinstance(obj, np.ndarray):
            f = io.BytesIO()
            np.save(f, obj)
            f.seek(io.SEEK_SET)
            data = f.read().decode('latin-1')
            return {'__numpy__': True, 'data': data}
        return super().default(obj)

json_dumps = partial(json.dumps, cls=NumpyEncoder)
json_dump = partial(json.dump, cls=NumpyEncoder)
json_loads = partial(json.loads, object_hook=as_numpy)
json_load = partial(json.load, object_hook=as_numpy)