What are hash tables used for in programming?

Hash tables in programming are used for efficient storage and quick retrieval of data by key. They implement a data structure where keys are transformed into an array index using a hash function, allowing operations like insertion, search, and deletion to be performed in approximately constant time O(1).

In Go, hash tables are implemented as the built-in map type. For example:

m := make(map[string]int)
m["apple"] = 5
fmt.Println(m["apple"]) // Outputs 5

Thus, hash tables are convenient for tasks where you need to quickly find elements by a unique key.