go语言——map

go语言——map

创建map

var map1 map[int]string
var map2 = make(map[int]string)
var map3 = map[string]int{"go":89,"python":90}

if map1 == nil{
    map1 = make(map[int]string)
    fmt.Println()
}

• 默认值：nil，相当于空
• nil的map，不能直接使用

map的使用

var map1 map[int]string
map1 = make(map[int]string)
// 根据key获得对应的value值，如果key存在，返回数值，不存在，获得value的零值
va1ue,ok = map1[4]
if ok {
    fmt.Println(value)
} else {
    fmt.Println("key不存在，获得零值")
}


//修改数据
fmt.Println(map1)
map1[1] = "agdgdglkadfk"
fmt.Println(map1)

//删除数据,key不存在则不影响
delete(map1,key:3)
fmt.Println(map1)
delete(map1,key:30)
fmt.Println(map1)

map的遍历

map1 := make(map[int]string)
map1[1] = "taincai"
map1[2] = "wudi"
map1[3] = "dsaffsda"

for k,v := range map1 {
	fmt.Println(k,v)
}

map与slice

	var map1 =  map[string]string{"小明":"sdfsdf"}
	var map2 = map[string]string{"小明":"sdfsdfsdfsdf"}
	var map3 = map[string]string{"小明":"sdfs5632df"}
	s1 := make([]map[string]string,0,3)
	s1 = append(s1,map1)
	s1 = append(s1,map2)
	s1 = append(s1,map3)
	for _,val := range s1 {
		fmt.Printf("小明：%s \n",val["小明"])
	}