Describe a scenario where you would prefer to use a map over a slice in Go and explain your reasoning.

You would prefer to use a map over a slice in Go when managing key-value pairs. A map allows you to associate values (the "values" in key-value pairs) with unique keys (the "keys" in key-value pairs). This data structure is ideal when you need to look up values quickly based on their corresponding keys. For example, if you are implementing a user authentication system and need to quickly check if a user ID exists and retrieve associated user data, a map would be more efficient than searching through a slice. It provides constant-time (O(1)) average case access to values by their keys, making it suitable for scenarios that require efficient key-based retrieval.