Accessing values using keys in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of accessing a nested dictionary value?

Given the dictionary data = {'user': {'name': 'Alice', 'age': 30}}, what is the output of print(data['user']['name'])?

Python

data = {'user': {'name': 'Alice', 'age': 30}}
print(data['user']['name'])

A KeyError

B 30

C Alice

D None

💡 Hint

Think about how to access values inside nested dictionaries using keys.

The key 'user' gives the nested dictionary {'name': 'Alice', 'age': 30}. Then accessing 'name' inside it returns 'Alice'.

❓ Predict Output

intermediate

What happens when accessing a missing key directly?

What error will this code produce?

info = {'city': 'Paris', 'country': 'France'}
print(info['population'])

Python

info = {'city': 'Paris', 'country': 'France'}
print(info['population'])

A KeyError

B Paris

C None

D TypeError

💡 Hint

What happens if you try to get a key that does not exist in a dictionary?

Accessing a key that is not present in the dictionary directly raises a KeyError.

❓ Predict Output

advanced

What is the output when using the get() method with a default value?

Consider the dictionary settings = {'theme': 'dark', 'font': 'Arial'}. What does print(settings.get('color', 'blue')) output?

Python

settings = {'theme': 'dark', 'font': 'Arial'}
print(settings.get('color', 'blue'))

A KeyError

B None

C color

D blue

💡 Hint

The get() method returns the default value if the key is missing.

Since 'color' is not a key in settings, get() returns the default 'blue'.

❓ Predict Output

advanced

What is the output when accessing a key with a mutable object as key?

What happens when running this code?

my_dict = {[1, 2]: 'value'}

Python

my_dict = {[1, 2]: 'value'}

A SyntaxError

B TypeError

C KeyError

D {[1, 2]: 'value'}

💡 Hint

Dictionary keys must be immutable types.

Lists are mutable and cannot be used as dictionary keys, so this raises a TypeError.

🧠 Conceptual

expert

How many items are in the dictionary after this code runs?

What is the number of items in result after executing this code?

keys = ['a', 'b', 'a', 'c']
values = [1, 2, 3, 4]
result = {k: v for k, v in zip(keys, values)}

A 3

B 1

C 2

D 4

💡 Hint

Dictionary keys must be unique; later values overwrite earlier ones.

The key 'a' appears twice; the last value (3) overwrites the first (1). So keys are 'a', 'b', 'c' → 3 items.