iOS Programming: The Big Nerd Ranch Guide

Enumerations and the Switch Statement

An enumeration is a type with a discrete set of values. Define an enum describing pies:

enum PieType {
    case Apple
    case Cherry
    case Pecan
}

let favoritePie = PieType.Apple

Swift has a powerful switch statement that, among other things, is great for matching on enum values:

let name: String
switch favoritePie {
case .Apple:
    name = "Apple"
case .Cherry:
    name = "Cherry"
case .Pecan:
    name = "Pecan"
}

The cases for a switch statement must be exhaustive: each possible value of the switch expression must be accounted for, whether explicitly or via a default: case. Unlike in C, Swift switch cases do not fall through – only the code for the case that is matched is executed. (If you need the ...