gistfile2.txt

$ 6g mapkey.go 
$ 6l mapkey.6 
$ ./6.out 
throw: runtime.mapaccess1: key not in map

panic PC=0x299ff8
throw+0x3e /Users/zimbatm/Code/golang/src/pkg/runtime/runtime.c:74
	throw(0x4ae9d, 0x0)
runtime.mapaccess1+0x74 /Users/zimbatm/Code/golang/src/pkg/runtime/hashmap.c:772
	runtime.mapaccess1(0x2a8230, 0x0)
main.main+0xb5 /Users/zimbatm/Code/learn/golang/mapkey.go:8
	main.main()
mainstart+0xf /Users/zimbatm/Code/golang/src/pkg/runtime/amd64/asm.s:54
	mainstart()
goexit /Users/zimbatm/Code/golang/src/pkg/runtime/proc.c:140
	goexit()

mapkey.go

package main

import "fmt"

func main() {
        var myMap = make(map[string]string);
        myMap["message"] = "world";
        fmt.Printf("hello, %s\n", myMap["wrongkey"])
}