go map 增删改查使用

package main

import "fmt"

func main()  {
   cites := make(map[string]string)
   cites["num1"] = "北京1"
   cites["num2"] = "北京2"
   cites["num3"] = "北京3"
   fmt.Println(cites)

   delete(cites,"num1")
   fmt.Println(cites)

   val, ok := cites["num2"]
   if ok {
      fmt.Println("有值,值是:",val)
   } else {
      fmt.Println("无值",val)
   }
}