Python json to object from model

Question

I know this looks like Frequency Ask Question mainly this question: How to convert JSON data into a Python object?

I will mention most voted answer:

import json
from types import SimpleNamespace

data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'

# Parse JSON into an object with attributes corresponding to dict keys.
x = json.loads(data, object_hook=lambda d: SimpleNamespace(**d))
print(x.name, x.hometown.name, x.hometown.id)

Based on that answer, x is object. But it's not object from model. I mean model that created with class. For example:

import json
from types import SimpleNamespace

class Hometown:
  def __init__(self, name : str, id : int):
    self.name = name
    self.id = id


class Person:  # this is a model class
  def __init__(self, name: str, hometown: Hometown):
    self.name = name
    self.hometown = hometown


data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'
x = Person(what should I fill here?) # I expect this will automatically fill properties from constructor based on json data 
print(type(x.hometown)) # will return Hometown class

I'm asking this is simply because my autocompletion doesn't work in my code editor if I don't create model class. For example if I type dot after object, it will not show properties name.

Maybe this might help: stackoverflow.com/questions/1639174/… It's tricky if dict is nested — Shashank
– Shashank, Commented Dec 14, 2022 at 10:56

Majid · Accepted Answer · 2022-12-14 10:56:01Z

2

This is how you can achieve that.

class Person:  # this is a model class
    def __init__(self, name: str, hometown: dict):
        self.name = name
        self.hometown = Hometown(**hometown)


x = Person(**json.loads(data))

answered Dec 14, 2022 at 10:56

Majid

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4 Comments

Citra Dewi Over a year ago

print(x.hometown.id) has return error 'dict' object has no attribute 'id'

Citra Dewi Over a year ago

print(x.hometown['id']) this will return 123 no error. I expect I can access id with dot instead of square bracket.

Majid Over a year ago

You can do it it like this there is no problem: x.hometown.id

Citra Dewi Over a year ago

Okay my fault I didn't see you modified Person class in hometown property.

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