What types of elements can be represented in a set?

In iOS, set elements (for example, in NSSet or Set in Swift) can be of any type that conforms to the Hashable protocol. This means that elements must have a unique hash and be comparable for equality.

Element types can be:

• Primitive types: Int, String, Double, etc.
• User-defined structures and classes that implement the Hashable protocol.

For example, in Swift:

let numbers: Set<Int> = [1, 2, 3]
let names: Set<String> = ["Anna", "Boris", "Viktor"]

struct Person: Hashable {
    let id: Int
    let name: String
}

let people: Set<Person> = [Person(id: 1, name: "Ivan"), Person(id: 2, name: "Maria")]

Thus, the set contains unique elements that can be of any type supporting hashing and comparison.