map function in Go

January 4, 2010


There is better stuff in the standard Go release but I wanted to try something for myself. In Go, this function is also called Map(), but is (of course) nicer. Anyhow, I’m liking this Go stuff more and more. Next I want to rewrite the DNS stuff in Go.

package main

import (

type e interface{}

func mult2(f e) e { 
    switch f.(type) {
    case int:
        return f.(int) * 2 
    case string:
        return f.(string) + f.(string)
    return f

func Map(n []e, f func(e) e) {
    for k, v := range n { 
        n[k] = f(v)

func main() {
    m := [...]e{1, 2, 3, 4}
    s := [...]e{"a", "b", "c", "d"}
    Map(&m, mult2)
    Map(&s, mult2)
    fmt.Printf("%v\n", m)
    fmt.Printf("%v\n", s)