Day 36/100: Working with JSON in Python

Welcome to Day 36 of your Python learning journey!
Today, we dive into a real-world skill: working with JSON data in Python.
JSON (JavaScript Object Notation) is everywhere—APIs, config files, databases, and web apps use it to store and exchange data.

Let’s learn how to read, write, parse, and manipulate JSON in Python with ease! 🧠

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📦 What is JSON?

JSON is a lightweight data format similar to Python dictionaries and lists.

Example JSON:

{
  "name": "Alice",
  "age": 30,
  "skills": ["Python", "Data Science"]
}

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📚 Python's json Module

Python provides a built-in module named json to handle JSON data.

import json

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📥 Converting JSON to Python (Deserialization)

You can load JSON strings into Python dictionaries using json.loads().

import json

json_str = '{"name": "Alice", "age": 30, "skills": ["Python", "Data Science"]}'
data = json.loads(json_str)

print(data["name"])  # Output: Alice
print(type(data))    # <class 'dict'>

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📤 Converting Python to JSON (Serialization)

You can convert Python objects (dict, list, etc.) into JSON strings using json.dumps().

person = {
    "name": "Bob",
    "age": 25,
    "skills": ["JavaScript", "React"]
}

json_data = json.dumps(person)
print(json_data)

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📝 Pretty Printing JSON

You can format JSON output with indentation for better readability:

print(json.dumps(person, indent=2))

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📁 Reading JSON from a File

with open('data.json', 'r') as file:
    data = json.load(file)

print(data["name"])

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💾 Writing JSON to a File

with open('output.json', 'w') as file:
    json.dump(person, file, indent=4)

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🔁 JSON and Python Data Types

JSON	Python
Object	dict
Array	list
String	str
Number	int/float
true/false	True / False
null	None

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🧨 Handling Errors

When working with JSON, handle decoding errors using try-except.

try:
    data = json.loads('{"name": "Alice", "age": }')  # Invalid JSON
except json.JSONDecodeError as e:
    print("Error parsing JSON:", e)

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✅ Practical Use Case: Fetching API Data

import requests
import json

response = requests.get("https://jsonplaceholder.typicode.com/users")
users = response.json()

for user in users:
    print(user['name'], '-', user['email'])

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🛠️ Summary

• Use json.loads() to parse JSON strings.
• Use json.dumps() to create JSON strings from Python data.
• Use json.load() and json.dump() to work with JSON files.
• JSON is used widely in APIs, config files, and more.

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