Guard
Guard can be used to reduce indentation on the happy path. In a guard statement, the else branch must transfer control to exit the code block containing the guard statement. This can be done with return, break, continue, or throw.
Simple guard
func divide(x: Int, y: Int) -> Int? {
guard y != 0 else {
print("You cannot divide by 0.")
return nil
}
let answer = x / y
return answer
}
print(divide(x: 5, y: 0))
// Output:
// You cannot divide by 0.
// nil
Guard let
func greet(name: String?) {
guard let unwrapped = name else {
print("Hello guest!")
return
}
print("Hello \(unwrapped)!")
}
greet(name: "Asma")
greet(name: nil)
// Output:
// Hello Asma!
// Hello guest!
