switch

    i := 2 
    switch i {
    case 1:
        fmt.Println("one")
    case 2:
        fmt.Println("two")
    case 3:
        fmt.Println("three")
    }

没有 break，但是有default。

   switch time.Now().Weekday() {
    case time.Saturday, casetime.Sunday:
        fmt.Println("It's the weekend")
    default:
        fmt.Println("It's a weekday")
    }

不带表达式的 switch

    t := time.Now()
    switch {
    case t.Hour() < 12:
        fmt.Println("It's before noon")
    default:
        fmt.Println("It's after noon")
    }

用于类型开关

whatAmI := func(i interface{}) {
    switch t := i.(type) {
    case bool:
        fmt.Println("I'm a bool")
    case int:
        fmt.Println("I'm an int")
    default:
        fmt.Printf("Don't know type %T\n", t)
    }
}

whatAmI(true)
whatAmI(1)
whatAmI("hey")