package main import "fmt" func main() { m := make(map[string]int) m["number3"] = 3 checkKey := func(k string) { if n, ok := m[k]; ok { fmt.Printf("value for key '%s' is %d\n", k, n) } else { fmt.Printf("key '%s' doesn't exist in map\n", k) } } // get value for a key that exists checkKey("number3") // get value for a key that doesn't exist checkKey("number4") // remove a key delete(m, "number3") fmt.Printf("deleted key 'number3\n") checkKey("number3") // and now it doesn't exist }