Go language basics map supplement

In the previous section, we learned how to use map.

map can be defined in two ways, one is the standard way, assigning a value when declaring, and the other is make.

package main


import "fmt"


func main() {


    var stu1 = map[string]string{
        "Name":   "张三"，
        "Age":    "18"，
        "height": "188"， //每行都要以，结尾，
}


    stu2:=make(map[string]string，10)
    stu2["Name"] = "李四"
    stu2["Age"] = "170"
    stu2["height"] = "109"


    fmt.Println(stu1，stu2)
    //map[Age:18 Name:张三 height:188] map[Age:170 Name:李四 height:109]
}

Found a problem

I don’t know if you have found a problem with the map we are currently storing It seems that only one can be stored.

Generally speaking, I should have a list that stores student information one by one.

Pseudocode:

var student_list = [张三的信息，李四的信息，王五的信息，...]

But after playing for so long, there are still single pieces of information. It's bad, it's harmful.

The map is stored in the slice

We know the slice, is defined like this.

var names []string
var names = []string{}
var names = make([]string，0，10)

In the above, the lists are saved with basic types, strings, numbers, etc.

For something exciting, store the map directly in the list.

伪代码

var names = []map[string]string{}
//注意:map[string]string{}是切片里面值的类型，这个切片里面的每个值都是map类型

示例代码

package main


import "fmt"


func main() {
    //定义个类型是map的列表
    var names = []map[string]string{}
    var name1 = map[string]string{
        "Name": "张三"，
        "Age":  "18"，
}
    var name2 = map[string]string{
        "Name": "李四"，
        "Age":  "22"，
}
    names = append(names， name1， name2) //向列表中添加map
    fmt.Println(names)                  //[map[Age:18 Name:张三] map[Age:22 Name:李四]]
}

图解

map中保存切片

在以往的操作中，我们的map的key和value都是一个值。

那像一个人的爱好了，生活习惯了，等，都不止一个，所以，在map中，map的值(value)，应该能保存多个才对。

代码

package main


import "fmt"


func main() {
    //map中，value为切片类型
    var person_hoppy = map[string][]string{}
    person_hoppy["hoppy"] = []string{"吃"， "喝"， "拉"， "撒"}
    fmt.Println(person_hoppy)//map[hoppy:[吃 喝 拉 撒]]
}

图解

注:在map中，key只能是固定值，因为要通过key找值，所以key不能修改，value可以是任意类型。

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