A map maps keys to values.
The zero value of a map is nil. A nil map has no keys, nor can keys be added.
nil
The make function returns a map of the given type, initialized and ready for use.
make
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"])