Optionals in Swift

Optionals in Swift are a powerful feature that allows a variable to hold either a value or nil (no value). This helps handle the absence of a value safely and avoids runtime crashes caused by null pointers.

var name: String? // Can be nil or hold a string value

Unwrapping Optionals

1.Force Unwrapping

Access the value of an optional using ! if you are sure it contains a value. Force unwrapping a nil optional causes a runtime crash.

var name: String? = "Swift"
print(name!) 
// Output: Swift

2.Optional Binding

Use if let or guard let to safely unwrap optionals.

// Using if let
if let unwrappedName = name {
    print("Name: \(unwrappedName)")
} else {
    print("Name is nil")
}

// Using guard let 
func greet(person: String?) {
    guard let name = person else {
        print("Name is nil")
        return
    }
    print("Hello, \(name)!")
}

greet(person: "Swift")

3. Nil-Coalescing Operator (??)

Provide a default value for an optional when it is nil

let person = name ?? "Swift"
print("Hello, \(person)") // Output: Hello, Swift

4.Optional Chaining

struct Person {
    var address: String?
}

var person: Person? = Person(address: "123 Swift")
print(person?.address ?? "None") // Output: 123 Swift

5.Implicitly Unwrapped Optionals

Sometimes, we can declare an optional that will always have a value after being set. We can use ! instead of ?. Implicitly unwrapped optionals can lead to runtime crashes

var age: Int! = 25
print(age + 5) // Output: 30