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import json
# Define a custom JSON encoder class
class CustomEncoder(json.JSONEncoder):
def default(self, obj):
# Convert non-serializable objects to a serializable format
if isinstance(obj, MyCustomObject):
return obj.to_dict() # Assuming the object has a to_dict() method to convert it into a dictionary
return super().default(obj)
# Create an instance of the custom object
custom_obj = MyCustomObject()
try:
# Attempt to serialize the object to JSON
json_data = json.dumps(custom_obj, cls=CustomEncoder)
print(json_data)
except TypeError as e:
print("Error: Object is not JSON serializable")
print(e)
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Use the jsonpickle module to make Python set JSON serializable
Steps:
1- Install jsonpickle using pip. pip install jsonpickle
2- Execute jsonpickle.encode(object) to serialize custom Python Object.
Example:
import json
import jsonpickle
from json import JSONEncoder
sampleSet = {25, 45, 65, 85}
print("Encode set into JSON using jsonpickle")
sampleJson = jsonpickle.encode(sampleSet)
print(sampleJson)
# Pass sampleJson to json.dump() if you want to write it in file
print("Decode JSON into set using jsonpickle")
decodedSet = jsonpickle.decode(sampleJson)
print(decodedSet)
# to check if we got set after decoding
decodedSet.add(95)
print(decodedSet)
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import multiprocessing, json
class JSONEncoderWithDictProxy(json.JSONEncoder):
def default(self, o):
if isinstance(o, multiprocessing.managers.DictProxy):
return dict(o)
return json.JSONEncoder.default(self, o)
json.dumps(your_nested_d, cls=JSONEncoderWithDictProxy)
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import json
class MyClass:
def __init__(self, name, age):
self.name = name
self.age = age
class MyEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, MyClass):
return obj.__dict__ # Serialize the class instance to a dictionary
return super().default(obj)
# Create an instance of MyClass
obj = MyClass("John", 25)
# Serialize the instance to JSON
json_str = json.dumps(obj, cls=MyEncoder)
print(json_str)
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If the dict values are all serializable
It looks like simply passing the DictProxy through the dict constructor allows you to serialize the data to JSON. The example below is from Python 3.6:
>>> import multiprocessing, json
>>> m = multiprocessing.Manager()
>>> d = m.dict()
>>> d["foo"] = "bar"
>>> d
<DictProxy object, typeid 'dict' at 0x2a4d630>
>>> dict(d)
{'foo': 'bar'}
>>> json.dumps(d)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Object of type 'DictProxy' is not JSON serializable
>>> json.dumps(dict(d))
'{"foo": "bar"}'
As you can see, while d is a DictProxy, using json.dumps(dict(d)) instead of json.dumps(d) allowed the data to be serialized. If you are using json.dump, the same applies.
If some dict values are also DictProxies
Unfortunately, the above method does not work if a value in the DictProxy is also a DictProxy. Such a value is created in this example:
>>> import multiprocessing
>>> m = multiprocessing.Manager()
>>> d = m.dict()
>>> d["foo"] = m.dict()
The solution is to extend the json.JSONEncoder class to handle DictProxy objects, like so:
>>> import multiprocessing, json
>>> class JSONEncoderWithDictProxy(json.JSONEncoder):
def default(self, o):
if isinstance(o, multiprocessing.managers.DictProxy):
return dict(o)
return json.JSONEncoder.default(self, o)
>>> m = multiprocessing.Manager()
>>> d = m.dict()
>>> d["foo"] = m.dict()
>>> d["foo"]["bar"] = "baz"
>>> json.dumps(d, cls=JSONEncoderWithDictProxy)
'{"foo": {"bar": "baz"}}'
>>> # This also works:
>>> JSONEncoderWithDictProxy().encode(d)
'{"foo": {"bar": "baz"}}'
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import multiprocessing
if __name__ == '__main__':
manager = multiprocessing.Manager()
d = manager.dict()
import json
json.dumps(d.copy())