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Dictionaries

5 min read Quiz at the end

Dictionaries store key-value pairs: {'name': 'Alice', 'age': 30}. Access with dict['key'] or dict.get('key', default). Iterate with .items() for both keys and values. Ordered from Python 3.7 onwards.

Python Dictionaries

user = {"name": "Alice", "age": 28, "active": True}

print(user["name"])          # Alice
print(user.get("email", "")) # safe access

user["email"] = "a@b.com"   # add/update
del user["active"]

for key, val in user.items():
    print(f"{key}: {val}")

# Dict comprehension
squares = {x: x**2 for x in range(5)}

← Tuples Next: Sets →

Topic Quiz · 5 questions

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1. How do you safely get a value with a default?

💡 .get(key, default) returns the default instead of raising KeyError.

2. Which method returns all key-value pairs?

💡 .items() returns dict_items of (key, value) tuples.

3. Are dictionary keys ordered in Python 3.7+?

💡 From Python 3.7, dictionaries maintain insertion order as an implementation detail.

4. Which creates a dict from two lists?

💡 dict(zip(keys, values)) creates a dictionary from two parallel lists.

5. What does del dict[key] do?

💡 del dict[key] permanently removes the key and its value.

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Dictionaries

Python Dictionaries

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