Working with JSON files in Python - Mini Project: Build & Apply

Working with JSON files

📖 Scenario: You are managing a small library's book records. The library stores book information in JSON files. You want to read, update, and save this data using Python.

🎯 Goal: Learn how to load JSON data from a file, update it, and save it back to a JSON file using Python.

📋 What You'll Learn

Create a JSON data structure representing books

Load JSON data from a file

Update the JSON data by adding a new book

Save the updated JSON data back to a file

Print the updated JSON data

💡 Why This Matters

🌍 Real World

Many applications store data in JSON files because JSON is easy to read and write. Managing JSON files is common in web apps, configuration files, and data exchange.

💼 Career

Knowing how to work with JSON files is important for software developers, data analysts, and anyone working with APIs or configuration management.

1

Create initial JSON data

Create a variable called books that holds a list of dictionaries. Each dictionary should represent a book with these exact keys and values: {"title": "The Hobbit", "author": "J.R.R. Tolkien", "year": 1937} and {"title": "1984", "author": "George Orwell", "year": 1949}.

Python

# Create the list of books with two dictionaries
# Your code here

Need a hint?

Use a list with two dictionaries inside. Each dictionary has keys: title, author, and year.

2

Save JSON data to a file

Import the json module. Then open a file called library.json in write mode and save the books list to this file using json.dump().

Python

books = [
    {"title": "The Hobbit", "author": "J.R.R. Tolkien", "year": 1937},
    {"title": "1984", "author": "George Orwell", "year": 1949}
]

# Import json and save books to library.json
# Your code here

Need a hint?

Use import json. Then open the file with open("library.json", "w") and use json.dump(books, file) to save.

3

Load JSON data from the file and update it

Open the file library.json in read mode and load the JSON data into a variable called loaded_books using json.load(). Then add a new book dictionary {"title": "To Kill a Mockingbird", "author": "Harper Lee", "year": 1960} to loaded_books.

Python

import json

books = [
    {"title": "The Hobbit", "author": "J.R.R. Tolkien", "year": 1937},
    {"title": "1984", "author": "George Orwell", "year": 1949}
]

with open("library.json", "w") as file:
    json.dump(books, file)

# Load JSON data from library.json and add a new book
# Your code here

Need a hint?

Use with open("library.json", "r") as file and loaded_books = json.load(file). Then use loaded_books.append(...) to add the new book.

4

Save updated data and print it

Open library.json in write mode again and save the updated loaded_books list using json.dump(). Then print loaded_books to show the updated list.

Python

import json

books = [
    {"title": "The Hobbit", "author": "J.R.R. Tolkien", "year": 1937},
    {"title": "1984", "author": "George Orwell", "year": 1949}
]

with open("library.json", "w") as file:
    json.dump(books, file)

with open("library.json", "r") as file:
    loaded_books = json.load(file)

loaded_books.append({"title": "To Kill a Mockingbird", "author": "Harper Lee", "year": 1960})

# Save updated books and print loaded_books
# Your code here

Need a hint?

Open the file with open("library.json", "w") and save loaded_books with json.dump(). Then print loaded_books.