Golang map详解

map[KeyType]ValueType

// 方式1初始化
var userInfo = make(map[string]string)
userInfo["userName"] = "zhangsan"
userInfo["age"] = "20"
userInfo["sex"] = "男"
fmt.Println(userInfo)
fmt.Println(userInfo["userName"])

// 创建方式2，map也支持声明的时候填充元素
var userInfo2 = map[string]string {
    "username":"张三",
    "age":"21",
    "sex":"女",
}
fmt.Println(userInfo2)

// 遍历map
for key, value := range userInfo2 {
    fmt.Println("key:", key, " value:", value)
}

// 判断是否存在,如果存在  ok = true，否则 ok = false
value, ok := userInfo2["username2"]
fmt.Println(value, ok)

delete(map 对象, key)

// 删除map数据里面的key，以及对应的值
delete(userInfo2, "sex")
fmt.Println(userInfo2)

// 切片在中存放map
var userInfoList = make([]map[string]string, 3, 3)
var user = map[string]string{
    "userName": "张安",
    "age": "15",
}
var user2 = map[string]string{
    "userName": "张2",
    "age": "15",
}
var user3 = map[string]string{
    "userName": "张3",
    "age": "15",
}
userInfoList[0] = user
userInfoList[1] = user2
userInfoList[2] = user3
fmt.Println(userInfoList)

for _, item := range userInfoList {
    fmt.Println(item)
}

// 将map类型的值
var userinfo = make(map[string][]string)
userinfo["hobby"] = []string {"吃饭", "睡觉", "敲代码"}
fmt.Println(userinfo)

// 写一个程序，统计一个字符串中每个单词出现的次数。比如 "how do you do"
var str = "how do you do"
array := strings.Split(str, " ")
fmt.Println(array)
countMap := make(map[string]int)
for _, item := range array {
    countMap[item]++
}
fmt.Println(countMap)