Python Lists, Dictionaries & Tuples

Mastering the 4 fundamental built-in collection types

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Python provides four built-in collection types: Lists (ordered, mutable), Tuples (ordered, immutable), Sets (unordered, unique), and Dictionaries (key-value pairs).

Lists vs Dictionaries

List: fruits = ["apple", "banana", "cherry"]. Supports .append(), .pop(), slicing fruits[0:2].

Dictionary: person = {"name": "Sara", "role": "Dev"}. Fast O(1) key lookups.

Working with Lists and Dictionaries

Try It Yourself »

# List of courses
courses = ["HTML", "CSS", "JavaScript", "Python"]
courses.append("SQL")

# Dictionary of user data
user = {
    "username": "alex99",
    "level": 3,
    "completed": courses
}

print(f"User {user['username']} has completed {len(user['completed'])} courses.")
print(f"Latest completed course: {user['completed'][-1]}")

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Test Yourself With Exercise

+15 XP

Which Python collection type is defined with curly braces {} and stores key-value pairs?

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