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https://github.com/zincware/znjson

Package to Encode/Decode some common file formats to json
https://github.com/zincware/znjson

deserialization json python serialization

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Package to Encode/Decode some common file formats to json

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# ZnJSON

Package to Encode/Decode some common file formats to json

Available via ``pip install znjson``

In comparison to `pickle` this allows having readable json files combined with some
serialized data.

# Example

````python
import numpy as np
import json
import znjson

data = json.dumps(
obj={"data_np": np.arange(2), "data": [x for x in range(10)]},
cls=znjson.ZnEncoder,
indent=4
)
_ = json.loads(data, cls=znjson.ZnDecoder)
````
The resulting ``*.json`` file is partially readable and looks like this:

````json
{
"data_np": {
"_type": "np.ndarray_small",
"value": [
0,
1
]
},
"data": [
0,
1,
2,
3,
4
]
}
````

# Custom Converter

ZnJSON allows you to easily add custom converters.
Let's write a serializer for ``datetime.datetime``.

````python
from znjson import ConverterBase
from datetime import datetime

class DatetimeConverter(ConverterBase):
"""Encode/Decode datetime objects

Attributes
----------
level: int
Priority of this converter over others.
A higher level will be used first, if there
are multiple converters available
representation: str
An unique identifier for this converter.
instance:
Used to select the correct converter.
This should fulfill isinstance(other, self.instance)
or __eq__ should be overwritten.
"""
level = 100
representation = "datetime"
instance = datetime

def encode(self, obj: datetime) -> str:
"""Convert the datetime object to str / isoformat"""
return obj.isoformat()
def decode(self, value: str) -> datetime:
"""Create datetime object from str / isoformat"""
return datetime.fromisoformat(value)
````

This allows us to use this new serializer:
````python
znjson.config.register(DatetimeConverter) # we need to register the new converter first
json_string = json.dumps(dt, cls=znjson.ZnEncoder, indent=4)
json.loads(json_string, cls=znjson.ZnDecoder)
````

and will result in
````json
{
"_type": "datetime",
"value": "2022-03-11T09:47:35.280331"
}
````

If you don't want to register your converter to be used everywhere, simply use:

```python
json_string = json.dumps(dt, cls=znjson.ZnEncoder.from_converters(DatetimeConverter))
```