json.dumps()

Lesson 4 of 9 in Coddy's Python JSON course.

The json.dumps() function is a key component of Python's json module. It converts (serializes) a Python object into a JSON-formatted string.

Basic Usage

Here's the basic syntax of json.dumps():


import json

json_string = json.dumps(python_object)

The function takes a Python object (like a dictionary or a list) as input and returns a JSON-formatted string.

Example

Let's convert a Python dictionary to a JSON string:


import json

python_dict = {
    "name": "John",
    "age": 30,
    "city": "New York"
}

json_string = json.dumps(python_dict)
print(json_string)
# Output: {"name": "John", "age": 30, "city": "New York"}

Data Type Conversion

json.dumps() automatically handles the conversion of Python data types to their JSON equivalents:

Python dictionaries become JSON objects
Python lists become JSON arrays
Python strings become JSON strings
Python int and float become JSON numbers
Python True becomes JSON true
Python False becomes JSON false
Python None becomes JSON null

This function is essential when you need to serialize Python data for storage or transmission in a JSON format, such as when working with APIs or storing configuration data.

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

Challenge

Easy

Create a function that takes a Python object as input and returns a formatted JSON string with specific indentation and separators. The function should:

Use json.dumps() to convert the input object to a JSON string.
Set the indentation to 4 spaces.
Use a comma and a space (", ") as the item separator and a colon and a space (": ") as the key separator.
Ensure that all keys in the resulting JSON string are sorted alphabetically.

The following input will be provided:


{"name": "Alice", "age": 30, "city": "New York", "hobbies": ["reading", "painting"], "is_student": false}

Print the resulting formatted JSON string.

Try it yourself

import json

# Read input
input_str = input()
input_obj = json.loads(input_str)

# TODO: Write your code here
# Create a function that formats the input_obj as a JSON string
# with the specified requirements

# Print the result
print(result)

All lessons in Python JSON

1JSON Basics

Intro to JSON JSON vs Python Data Types The json Module

2Encoding JSON

json.dumps()Formatting JSON Output Custom JSON Encoding

3Decoding JSON

json.loads()Handling JSON Data Types Custom JSON Decoding