Working with JSON and XML - Digital Solutions 2025

JSON¶

JSON (JavaScript Object Notation) is a lightweight data format used to store and exchange data. It’s easy for humans to read and write, and easy for machines to parse and generate.

A JSON object is similar to a Python dictionary.

{
  "name": "Alice",
  "age": 25,
  "is_student": true,
  "courses": ["Math", "Science"]
}

Python and JSON¶

Python provides a built-in module called json to work with JSON data.

JSON to Python

Convert a JSON-formatted string into a Python dictionary.

What is a JSON-formatted string?

A JSON-formatted string is a text-based way to represent structured data using the JavaScript Object Notation (JSON) format. It uses key–value pairs and arrays to organize data, and it is commonly used for data exchange between systems, especially in web applications.

JSON Rules:

Keys and string values must be in double quotes (").
Values can be:
- Strings ("text")
- Numbers (123)
- Booleans (true, false)
- null
- Arrays ([ ])
- Nested objects ({ })

import json

json_string = '{"name": "Alice", "age": 25}'
python_dict = json.loads(json_string)
print(python_dict)
print(python_dict['name'])

Python to JSON

Convert a Python dictionary into a JSON-formatted string.

import json

data = {'name': 'Bob', 'age': 30, 'is_student': False}
json_string = json.dumps(data)
print(json_string)

Working with JSON Files¶

Reading from a JSON file

Open a JSON file, reads its JSON content, then convert it into a Python object, depending on the JSON file format:

key–value pair → dictionary
array → list

import json

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

Writing to a JSON file

Convert a Python dictionary into a JSON-formatted string and write it to a JSON file.

import json

data = {'name': 'Carol', 'age': 28}
with open('output.json', 'w') as file:
    json.dump(data, file, indent=4)

Advanced Tips

Use indent=4 to pretty-print JSON when writing.
Use sort_keys=True to alphabetically sort dictionary keys in output.
Use json.loads(json_string) for strings and json.load(file) for files.

Summary¶

Task	Method
JSON String → Python Object	`json.loads()`
Python Object → JSON String	`json.dumps()`
JSON File → Python Object	`json.load()`
Python Object → JSON File	`json.dump()`

JSON Activities

Activity 1: Decode a JSON String

You are given a JSON string that represents a book in a digital library. Convert it to a Python dictionary and print each piece of information.

JSON String:

json_data = '{"title": "The Hobbit", "author": "J.R.R. Tolkien", "year": 1937, "available": true}'

Instructions:

Import the json module.
Convert the json_data string to a Python dictionary using json.loads().
Print out the book title, author, year, and availability status in a readable format.

Expected Output:

Title: The Hobbit  
Author: J.R.R. Tolkien  
Year: 1937  
Available: True

Activity 2: Read a JSON List of Students

You receive JSON data representing a list of students. Convert it into a Python list of dictionaries and print the name and grade for each student.

JSON String:

students_json = '''
[
    {"name": "Alice", "grade": 90},
    {"name": "Bob", "grade": 85},
    {"name": "Carol", "grade": 95}
]
'''

Instructions:

Import the json module.
Use json.loads() to convert students_json into a Python list.
Loop through each student and print their name and grade.

Expected Output:

Alice: 90  
Bob: 85  
Carol: 95

Activity 3: Read a Single Object from a JSON File

You are given a file named car.json that contains information about a vehicle. Your job is to load the file into Python and display the data.

Instructions:

Use Python to open and read car.json.
Convert the JSON file into a Python dictionary using json.load().
Print out each property in the following format:

Expected Output:

Make: Toyota  
Model: Corolla  
Year: 2020  
Electric: False

Activity 4: Read a List of Objects from a JSON File

You are given a file called inventory.json which contains a list of items in a school store. Convert the data to a Python list and display the stock level for each item.

Instructions:

Open and read the inventory.json file in Python.
Convert the JSON data to a Python list of dictionaries.
Loop through the list and print each item with its stock level:

Expected Output:

Pencil: 120  
Notebook: 60  
Eraser: 35

Activity 5: Convert a Python Dictionary to a JSON String

You are building a simple digital contact book. Start with a Python dictionary and convert it to a JSON string so it can be stored or sent over a network.

Instructions:

Create a Python dictionary with the following details:

contact = {
    "name": "Liam",
    "phone": "0455 123 456",
    "email": "liam@example.com",
    "subscribed": True
}

Use json.dumps() to convert the dictionary into a JSON-formatted string.
Print the resulting JSON string.
Add indent=4 to make the output easier to read.

Expected Output (formatted):

{
    "name": "Liam",
    "phone": "0455 123 456",
    "email": "liam@example.com",
    "subscribed": true
}

Activity 6: Save Python Data to a JSON File

You are creating a list of movies for a media app. Convert the data from Python to JSON and save it to a file called movies.json.

Instructions:

Create the following Python list of dictionaries:

movies = [
    {"title": "Inception", "year": 2010},
    {"title": "The Matrix", "year": 1999},
    {"title": "Interstellar", "year": 2014}
]

Use json.dump() to save this data to a file named movies.json.
Include indent=2 when saving to make the JSON file readable.

Expected Result (movies.json file):

[
  {
    "title": "Inception",
    "year": 2010
  },
  {
    "title": "The Matrix",
    "year": 1999
  },
  {
    "title": "Interstellar",
    "year": 2014
  }
]

XML¶

XML (eXtensible Markup Language) is a markup language used to store and transport data. It’s similar to HTML but focuses on describing data rather than displaying it.

Example XML:

<student>
    <name>Alice</name>
    <age>25</age>
    <courses>
        <course>Math</course>
        <course>Science</course>
    </courses>
</student>

Python and XML¶

Python includes a built-in module called xml.etree.ElementTree (often shortened to ET) for parsing and creating XML data.

Parsing XML from a String

This code parses an XML string into a Python XML element.

What is an XML Element?

A Python XML element is an object—specifically, an instance of the xml.etree.ElementTree.Element class. It behaves like an object with methods (e.g., .find(), .text, .attrib) that allow you to navigate and manipulate XML data.

import xml.etree.ElementTree as ET

xml_data = """
<student>
    <name>Alice</name>
    <age>25</age>
</student>
"""

root = ET.fromstring(xml_data)
print(root.tag)  # Output: student
print(root.find('name').text)  # Output: Alice
print(root.find('age').text)   # Output: 25

Parsing XML from a File

Create an XML element from a string and access its child elements.

student.xml:

<student>
    <name>Bob</name>
    <age>22</age>
</student>

Python code:

tree = ET.parse('student.xml')
root = tree.getroot()

print(root.find('name').text)  # Output: Bob
print(root.find('age').text)   # Output: 22

Looping Through Elements

Parse an XML string containing multiple students, then loops through each <student> element to print their name and age in a formatted sentence.

xml_data = """
<students>
    <student>
        <name>Alice</name>
        <age>25</age>
    </student>
    <student>
        <name>Bob</name>
        <age>22</age>
    </student>
</students>
"""

root = ET.fromstring(xml_data)

for student in root.findall('student'):
    name = student.find('name').text
    age = student.find('age').text
    print(f"{name} is {age} years old")

Creating an XML Document

import xml.etree.ElementTree as ET

root = ET.Element("student")
name = ET.SubElement(root, "name")
name.text = "Carol"
age = ET.SubElement(root, "age")
age.text = "23"

tree = ET.ElementTree(root)
tree.write("new_student.xml", encoding="utf-8", xml_declaration=True)

Summary¶

Task	Method
Parse from string	`ET.fromstring(xml_string)`
Parse from file	`ET.parse(file)`
Find element	`element.find('tag')`
Find all elements	`element.findall('tag')`
Get element text	`element.text`
Write to XML file	`tree.write('file.xml')`

XML Activities

Activity 1: Parse an XML String into Python

You are given a string containing XML data about a book. Convert it to Python using ElementTree, and print the values of each tag.

XML Data (as a string):

xml_data = '''
<book>
    <title>1984</title>
    <author>George Orwell</author>
    <year>1949</year>
</book>
'''

Instructions:

Import xml.etree.ElementTree as ET.
Use ET.fromstring(xml_data) to parse the XML into a Python object.
Print the title, author, and year from the XML.

Expected Output:

Title: 1984  
Author: George Orwell  
Year: 1949

Activity 2: Read XML from a File and Loop Through Elements

You are working with an XML file named students.xml that contains multiple student records. Load the file and display each student’s name and age.

Instructions:

Use ET.parse('students.xml') and get the root with .getroot().
Loop through each <student> element.
Print the name and age of each student.

Expected Output:

Alice is 25 years old  
Bob is 22 years old

Activity 3: Convert a Python Dictionary to an XML Element

You have a dictionary with information about a movie. Convert it to an XML structure and print it.

Python Dictionary:

movie = {
    "title": "The Matrix",
    "director": "The Wachowskis",
    "year": "1999"
}

Instructions:

Import xml.etree.ElementTree as ET.
Create a root element called <movie>.
Add child elements for title, director, and year, using the values from the dictionary.
Print the resulting XML string using ET.tostring().

Expected Output (formatted):

<movie>
    <title>The Matrix</title>
    <director>The Wachowskis</director>
    <year>1999</year>
</movie>

Activity 4: Create an XML File from a List of Dictionaries

You are given a Python list of people. Convert it into XML and save it to a file called people.xml.

Python List:

people = [
    {"name": "Alice", "age": "30"},
    {"name": "Bob", "age": "25"}
]

Instructions:

Create a root element called <people>.
For each person in the list, create a <person> sub-element with <name> and <age> inside.
Use ET.ElementTree() to write the XML to people.xml.

Expected Output (people.xml):

<people>
    <person>
        <name>Alice</name>
        <age>30</age>
    </person>
    <person>
        <name>Bob</name>
        <age>25</age>
    </person>
</people>