In golang is there a nice way of getting a slice of values from a map?

If I have a map m is there a better way of getting a slice of the values v then

package main
import (
  "fmt"
)

func main() {
    m := make(map[int]string)

    m[1] = "a"
    m[2] = "b"
    m[3] = "c"
    m[4] = "d"

    // Can this be done better?
    v := make([]string, len(m), len(m))
    idx := 0
    for  _, value := range m {
       v[idx] = value
       idx++
    }

    fmt.Println(v)
 }

Is there a built feature of a map? Is there a function in a Go package, or is this the best code to do if I have to?