How to dynamically build a JSON object?

python

json-engineering

dataframe

best-practices

byAlex Kataev·Oct 9, 2024

Creating a dynamic JSON object in Python? No worries! Use a dict object, append your data, and then serialize it:

import json

# Let's make our first ever JSON object
json_obj = {'name': 'Alice', 'age': 25}
# Wait Alice is missing her email, let's add that ...
json_obj['email'] = '[email protected]'

# Voila! A dynamic JSON object!
json_str = json.dumps(json_obj)

Now enjoy the sweet result: {"name": "Alice", "age": 25, "email": "[email protected]"}. You're free to keep adding or modifying json_obj.

Common pitfalls

Be the savvy JSON maker by avoiding these common blunders:

Remember that json.dumps({}) gives you a string, not a dictionary.
Build your stories using Python dictionaries, then use json.dumps() when you're ready to spin it into a JSON tale.
For custom objects, direct their transformations using object_hook in json.loads().
For more bells and whistles, consider using ObjDict and EasyDict. They're akin to having your very own JSON toolbox.

Useful libraries and tricks

The universe of Python offers some libraries and utilities to enhance your JSON building experience:

ObjDict: This library can make your JSON look neat and tidy. It offers dot notation and ensures the natural order of your JSON structure remains intact.
SimpleNamespace: Use this when you're playing with API responses. It lets you access JSON values like attributes.
EasyDict: It simplifies your exploration in the complex world of JSON. It's like a recursive map to all treasures hidden inside.

Handling Complex scenarios

As your JSON objects grow larger and complex:

Break down your requirements. Make nested dictionaries when required and combine them as a whole before converting to JSON.
Watch out for TypeErrors. They usually pop up when trying to convert unsupported types to JSON.

Advanced Conversions

When the going gets tough, Python gets tougher...

Use object_hook in json.loads. It helps you decode JSON objects into complex Python objects.
Inherit from json.JSONEncoder. This will let you control how objects get converted to JSON.