(Go Lang) Switch (GBEN)

Go by Example

Example

  • Like C
  • switch / case / default
  • Multiple comma separated conditions per case
  • case on interface type
    • Interface types not yet introduced

// Here’s a basic switch.
i := 2
fmt.Print("Write ", i, " as ")
switch i {
case 1:
  fmt.Println("one")
case 2:
  fmt.Println("two")
case 3:
  fmt.Println("three")
}
// You can use commas to separate multiple expressions in the same case
// statement. We use the optional default case in this example as well.
switch time.Now().Weekday() {
case time.Saturday, time.Sunday:
  fmt.Println("It's the weekend")
default:
  fmt.Println("It's a weekday")
}
// switch without an expression is an alternate way to express if/else logic.
// Here we also show how the case expressions can be non-constants.
t := time.Now()
switch {
case t.Hour() < 12:
  fmt.Println("It's before noon")
default:
  fmt.Println("It's after noon")
}
// A type switch compares types instead of values. You can use this to
// discover the the type of an interface value. In this example, the variable
// t will have the type corresponding to its clause.
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")
Write 2 as two
It's a weekday
It's after noon
I'm a bool
I'm an int
Don't know type string

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