Lesson 13 Quiz: Dictionaries: Labeled Storage

1. What is a dictionary, and what are its two parts?

A. Labeled storage: each entry has a key (the label) and a value. B. Ordered storage: each entry has a position number and a value. C. Labeled storage: each entry has a value but no label. D. A list of labels with no values at all.

2. How is a dictionary different from a list?

A. A list finds items by label; a dictionary finds them by position. B. A list finds items by position; a dictionary finds them by label. C. A list finds items by label; a dictionary finds them by position number too. D. There is no difference — they work exactly the same way.

3. What happens if you ask for a key that does not exist?

A. Python returns nothing (`None`). B. Python creates the key with an empty value. C. Python prints the whole dictionary instead. D. A `KeyError`.

4. What is the difference between `student["age"] = 10` and `student["pet"] = "Biscuit"`?

A. The first adds a new entry; the second replaces an existing entry. B. Both replace an existing entry. C. The first replaces an existing entry; the second adds a new one — Python decides by whether the key already exists. D. Both add a new entry.

5. Why is `str(value)` needed in the loop that prints `key + ": " + str(value)`?

A. Because `+` cannot join text and a number directly, so the number must first be converted to text. B. Because `str()` makes numbers bigger before printing. C. Because `+` only works inside loops. D. Because the key must be a number too, or the loop fails.