What are optionals in Swift?

In Swift, optionals are types that can contain either a value of a certain type or nil (absence of a value). They are used for safe handling of variables that may not have a value, helping to avoid errors related to null references.

An optional is declared with a question mark ? after the type, for example:

var name: String? // variable can contain a string or nil

To access the value of an optional, it must be "unwrapped", for example, using an if let construct:

if let actualName = name {
    print("Name: \(actualName)")
} else {
    print("Name is missing")
}

Optionals ensure type safety and help avoid errors related to nil, making the code more reliable and readable.