Go by Example: Switch

Switch statements express conditionals across many branches.

package main
import "fmt"
import "time"
func main() {

Here’s a basic switch.

    i := 2
    fmt.Print("Write ", i, " as ")
    switch i {
    case 1:
    case 2:
    case 3:

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")
        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")
        fmt.Println("It's after noon")

A type switch compares types instead of values. You can use this to discover 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")
            fmt.Printf("Don't know type %T\n", t)
$ go run switch.go 
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

Next example: Arrays.