A switch statement is another way to write a sequence of if-else statements.

Go’s switch is like the one in C and C++ except that it only runs the selected case, not all the cases that follow we don’t need a break statement here.

switch expression {
    case exp1:
        //Executes if expression matches exp1
    case exp2:
        //Executes if expression matches exp2
    default:
        //Executes if expression does not matches with any case
}

Switch evaluation order

Switch cases evaluate cases from top to bottom and stop when a case succeeds.

In the below example, it checks case "Linux": if os matches Linux then stop at that case else goes to the next case.

package main

import (
    "fmt"
    "runtime"
)

func main() {
    //Prints which OS you're using
    switch os := runtime.GOOS; os {
    case "linux":
        fmt.Println("Linux.")
    case "darwin":
        fmt.Println("OS X.")
    default:
        fmt.Printf("%s.\n", os)
    }
}

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Switch with NO condition

Switch with no condition is like switch true. It is useful for writing a long if-else-if ladder.

package main

import (
    "fmt"
    "time"
)

func main() {
    t := time.Now()
    switch {
    case t.Hour() < 12:
        fmt.Println("Good morning!")
    case t.Hour() < 17:
        fmt.Println("Good afternoon.")
    default:
        fmt.Println("Good evening.")
    }
}

Run this code in Go Playground

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