A map maps keys to values.
Maps must be created with make (not new) before use; the nil map is empty and cannot be assigned to.
package main
import "fmt"
type Vertex struct{
Lat, Long float64
}
var m map[string]Vertex
func main() {
m = make(map[string]Vertex)
m["Bell Labs"] = Vertex{
40.68433, -74.39967,
}
fmt.Println(m["Bell Labs"])
}