json2np.py

import json


class EncodeFromNumpy(json.JSONEncoder):
    """
    - Serializes python/Numpy objects via customizing json encoder.
    - **Usage**
        - `json.dumps(python_dict, cls=EncodeFromNumpy)` to get json string.
        - `json.dump(*args, cls=EncodeFromNumpy)` to create a file.json.
    """

    def default(self, obj):
        import numpy

        if isinstance(obj, numpy.ndarray):
            return {"_kind_": "ndarray", "_value_": obj.tolist()}
        if isinstance(obj, numpy.integer):
            return int(obj)
        elif isinstance(obj, numpy.floating):
            return float(obj)
        elif isinstance(obj, range):
            value = list(obj)
            return {"_kind_": "range", "_value_": [value[0], value[-1] + 1]}
        return super(EncodeFromNumpy, self).default(obj)


class DecodeToNumpy(json.JSONDecoder):
    """
    - Deserilizes JSON object to Python/Numpy's objects.
    - **Usage**
        - `json.loads(json_string,cls=DecodeToNumpy)` from string, use `json.load()` for file.
    """

    def __init__(self, *args, **kwargs):
        json.JSONDecoder.__init__(self, object_hook=self.object_hook, *args, **kwargs)

    def object_hook(self, obj):
        import numpy

        if "_kind_" not in obj:
            return obj
        kind = obj["_kind_"]
        if kind == "ndarray":
            return numpy.array(obj["_value_"])
        elif kind == "range":
            value = obj["_value_"]
            return range(value[0], value[-1])
        return obj