12.map

package main
import "fmt"
func main() {
    //声明mymap是一种map类型 key是String，value是String类型
    var myMap1 map[string]string
    if myMap1 == nil {
        fmt.Println("myMap是一个空map")
    }
    //需要先用make给map分配数据空间
    myMap1=make(map[string]string,10)
    myMap1["one"]="java"
    myMap1["two"]="c++"
    myMap1["three"]="go"
    fmt.Println(myMap1)
    //第二种声明方式
    myMap2:=make(map[int]string)
    myMap2[1]="java"
    myMap2[2]="c++"
    myMap2[3]="python"
    fmt.Println(myMap2)
    myMap3 :=map[int]string{
        1:"php",
        2:"go",
        3:"java",
    }
    fmt.Println(myMap3)
}

package main
import "fmt"
func printMap(cityMap map[string]string)  {
    //引用传递
    for key, value := range cityMap {
        fmt.Println(key,value)
    }
}
func main() {
    cityMap :=make(map[string]string)
    //添加
    cityMap["China"]="Beijing"
    cityMap["japan"]="tokyo"
    fmt.Println(cityMap)
    //遍历
    for key, value := range cityMap {
        fmt.Println(key,value)
    }
    //删除
    delete(cityMap,"japan")
    printMap(cityMap)
}