Golang中map的三种声明方式和简单实现增删改查

package main import ( "fmt" ) func main() { test3 := map[string]string{ "one":   "php", "two":   "golang", "three": "java", } no_exsits, ok := test3["three"] fmt.Println(no_exsits, ok) if no_exsits, ok := test3["four"]; ok { fmt.Println(no_exsits) } else { fmt.Println("KEY not exist") } } //java true //KEY not exist

map就相当于php语言中的关联数组

//代码
package main import ( "fmt" ) func main() { //第一种声明
    var test1 map[string]string
    //在使用map前，需要先make，make的作用就是给map分配数据空间
    test1 = make(map[string]string, 10) test1["one"] = "php" test1["two"] = "golang" test1["three"] = "java" fmt.Println(test1) //map[two:golang three:java one:php] //第二种声明
    test2 := make(map[string]string) test2["one"] = "php" test2["two"] = "golang" test2["three"] = "java" fmt.Println(test2) //map[one:php two:golang three:java] //第三种声明
    test3 := map[string]string{ "one" : "php", "two" : "golang", "three" : "java", } fmt.Println(test3) //map[one:php two:golang three:java]
 language := make(map[string]map[string]string) language["php"] = make(map[string]string, 2) language["php"]["id"] = "1" language["php"]["desc"] = "php是世界上最美的语言" language["golang"] = make(map[string]string, 2) language["golang"]["id"] = "2" language["golang"]["desc"] = "golang抗并发非常good" fmt.Println(language) //map[php:map[id:1 desc:php是世界上最美的语言] golang:map[id:2 desc:golang抗并发非常good]] //增删改查 // val, key := language["php"] //查找是否有php这个子元素 // if key { // fmt.Printf("%v", val) // } else { // fmt.Printf("no"); // } //language["php"]["id"] = "3" //修改了php子元素的id值 //language["php"]["nickname"] = "啪啪啪" //增加php元素里的nickname值 //delete(language, "php") //删除了php子元素
 fmt.Println(language) }

 补充：判断一个不存在的key

package main

import (
    "fmt"
)

func main() {
    test3 := map[string]string{
        "one":   "php",
        "two":   "golang",
        "three": "java",
    }
    no_exsits, ok := test3["three"]
    fmt.Println(no_exsits, ok)
    if no_exsits, ok := test3["four"]; ok {
        fmt.Println(no_exsits)
    } else {
        fmt.Println("KEY not exist")
    }

}
//java true
//KEY not exist