Python: Serialising and Deserialising JSON

JSON stands for JavaScript Object Notation and it is one of the most popular data formats to store and transfer data between two points. Python has a built-in module called json that we can use to work with JSON.

Deserialising JSON in Python

We can parse a string of JSON into a Python dictionary using the loads() function in the json module:

import json

json_str = '{ "name": "Timmy Turner", "age": 10, "show": "The Fairly OddParents"}'

parsed = json.loads(json_str)

print(parsed)

{'name': 'Timmy Turner', 'age': 10, 'show': 'The Fairly OddParents'}

While it looks the same as the input, because it is a dictionary, you can access it like you would any dictionary:

import json

json_str = '{ "name": "Timmy Turner", "age": 10, "show": "The Fairly OddParents"}'

parsed = json.loads(json_str)

print(parsed["name"])
print(parsed["age"])
print(parsed["show"])

Timmy Turner
10
The Fairly OddParents 

Serialising Object to JSON in Python

You can do the reverse and convert a Python object into a string of JSON using the dumps() function:

import json

obj = {
    "name": "Timmy Turner",
    "age": 10,
    "show": "The Fairly OddParents"
}

converted = json.dumps(obj)

print(converted)

{"name": "Timmy Turner", "age": 10, "show": "The Fairly OddParents"}

Formatting JSON

When you are outputting to JSON, you can pass optional parameters to the dumps() function to format the output for us.

Here's how to indent the string to make it more readable:

import json

obj = {
    "name": "Timmy Turner",
    "age": 10,
    "show": "The Fairly OddParents"
}

converted = json.dumps(obj, indent=4)

print(converted)

{
    "name": "Timmy Turner",
    "age": 10,
    "show": "The Fairly OddParents"
}

• Python Docs - JSON