Swift基础 枚举

枚举

使用枚举会使得编程的过程更加安全，因为一旦使用了不是枚举的值，系统就会立刻给出反馈。

	enum Direction{
    
    
        case North
		case South
		case East
		case West
	}
    
    let directuin = Direction.South
    
    switch directuin {
    
    
    case .North:
        print("North")
    case .South:
        print("South")
    case .East:
        print("East")
    case .West:
        print("West")
    default:
        print("")
    }

更简洁的声明方式：

	enum Direction{
    
    
		case North,South,East,West
	}

设置枚举值

	enum Direction:Int{
    
    
        case North = 1
		case South = 2
		case East = 3
		case West = 4
	}

	enum Direction:String{
    
    
        case North = "North"
		case South = "South"
		case East = "East"
		case West = "West"
	}

获取枚举值

	enum Direction:String{
    
    
        case North = "North"
		case South = "South"
		case East = "East"
		case West = "West"
	}
	print(Direction.North.rawValue)

遍历枚举

枚举需要继承CaseIterable才能使得枚举具有可遍历的特性。

enum TestEnum:CaseIterable{
    
    
    case A
    case B
    case C
}

print(TestEnum.allCases)

运行结果：

[__lldb_expr_1.TestEnum.A, __lldb_expr_1.TestEnum.B, __lldb_expr_1.TestEnum.C]
//结果是一个数组