【GO】复合类型：映射

package main
import "fmt"
func main010() {
  var countryCapitalMap map[string]string
  /* create a map*/
  countryCapitalMap = make(map[string]string)
  /* insert key-value pairs in the map*/
  countryCapitalMap["France"] = "Paris"
  countryCapitalMap["Italy"] = "Rome"
  countryCapitalMap["Japan"] = "Tokyo"
  countryCapitalMap["India"] = "New Delhi"
  /* print map using keys*/
  for country := range countryCapitalMap {
    fmt.Println("Capital of", country, "is", countryCapitalMap[country])
  }
  /* test if entry is present in the map or not*/
  capital, ok := countryCapitalMap["United States"]
  fmt.Println("咔咔打印", ok)
  /* if ok is true, entry is present otherwise entry is absent*/
  if ok {
    fmt.Println("Capital of United States is", capital)
  } else {
    fmt.Println("Capital of United States is not present")
  }
}
func main() {
  // 映射定义的几种方式
  //var scoreMap map[string]int = map[string]int{}
  //var scoreMap = map[string]int{}
  //scoreMap := map[string]int{}
  // 没有指定长度，一开始就是0
  scoreMap := make(map[string]string)
  scoreMap["咔咔博客地址"] = "blog.fangkang.top"
  scoreMap["咔咔手赚网地址"] = "fangkang.top"
  // 根据键值访问值
  fmt.Println("咔咔博客地址为", scoreMap["咔咔博客地址"])
  fmt.Println("咔咔手赚网地址为", scoreMap["咔咔手赚网地址"])
  // 修改键值
  scoreMap["咔咔手赚网地址"] = "https://fangkang.top"
  fmt.Println("咔咔手赚网地址", scoreMap["咔咔手赚网地址"])
  // 带校验的访问键值  这里的ok返回true  和 false
  notExist, ok := scoreMap["不存在的键值"]
  if ok {
    fmt.Println("存在的啊")
  }
  // 关于上边用:=  这里用 =  简单说明一下  上边的定义赋值在一起  下面只是进行赋值
  notExist, ok = scoreMap["咔咔博客地址"]
  if ok {
    fmt.Println(notExist)
  }
  // 访问一个不存在的键
  fmt.Println("咔咔手赚网地址", notExist, ok)
}
/**
对映射进行遍历
*/
func main123() {
  scoreMap := map[string]string{}
  scoreMap["咔咔博客地址"] = "blog.fangkang.top"
  scoreMap["咔咔手赚网地址"] = "fangkang.top"
  // %s 代表的是字符串
  for key, value := range scoreMap {
    fmt.Printf("scoreMap[%s]=%s\n", key, value)
  }
}