How do dictionaries work in Python?

How do dictionaries work in Python and why are they useful?

Expected Answer

Dictionaries store key-value pairs and provide fast lookup by key for hashable keys.

Detailed Explanation

A strong answer mentions key uniqueness, hashability, common operations, and practical use cases such as configuration, counts, and profiles.

Common Follow-up Questions

• What can be used as a key?
• How would you count values?