How to serialize object to json with custom fields in python

Question

I have a class

class Person(object):
    def __init__(self,age,name):
        self.person_age = age
        self.person_name = name

And i want to serialize object to json. I can do so:

person = Person(20,'Piter')
person.__dict__

But such an approach will return it:

{'person_age':20,person_name:'Piter'}

I want serialize my object to json with my own fields. Instead of 'person_age' - 'age'. Instead of 'person_name' - 'name':

{'age':20,name:'Piter'}

How can this be done if the class has many fields?

Use [DRF Serializers](https://www.django-rest-framework.org/api-guide/serializers/) — JPG, Mar 21 '20 at 15:13
So you have a mapping of object fields to json fields? Something like `{'person_name' : 'name', 'person_age':'age'}`? — Dani Mesejo, Mar 21 '20 at 15:14
You could look into jsonpickle. https://stackoverflow.com/a/8614096 — quamrana, Mar 21 '20 at 15:15
@DaniMesejo Then you must use all fields. There may be many. And I only need some — Pikachu, Mar 21 '20 at 15:17
@Pikachu - I hope the solution for [this question](https://stackoverflow.com/questions/60307608/is-it-a-good-practice-to-use-dto-in-the-service-layer/) worked for you. Do not forget to accept the answer so that future visitors can also use the solution confidently. Feel free to comment in case of any doubt/issue. — Arvind Kumar Avinash, May 24 '20 at 11:29

score 5 · Accepted Answer · answered Mar 21 '20 at 15:21

IIUC, you could do the following:

import json


class Person(object):
    def __init__(self, age, name, weight):
        self.person_age = age
        self.person_name = name
        self.weight = weight


p = Person(30, 'Peter', 78)
mapping = {'person_age': 'age', 'person_name': 'name'}
result = json.dumps({mapping.get(k, k): v for k, v in p.__dict__.items()})

print(result)

Output

{"age": 30, "name": "Peter", "weight": 78}

Note that you only need those names you want to change, in the example above weight remains unchanged.

sattva_venu · Answer 2 · 2020-03-21T15:35:18.713

-1

You can use json module to serialize the object to json format.

Here is the example:-

import json
class Person(object):
    def __init__(self,age,name):
        self.person_age = age
        self.person_name = name

person = Person(20,'Piter')

person_JSON = json.dumps(person.__dict__)
print(person_JSON)

Output:-

'{"person_age": 20, "person_name": "Piter"}'

edited Mar 21 '20 at 15:35

answered Mar 21 '20 at 15:28

sattva_venu

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He specifically asked to have custom field names when serializing. – Daan May 02 '22 at 15:16
@Daan, nin hendran I have written the code with respect to the question asked. Let me know what exactly is the issue you saw with my code. – sattva_venu May 18 '22 at 17:35

How to serialize object to json with custom fields in python

2 Answers2