go结构体嵌套的切片数组操作-编程学习网

看代码吧~


package main
import (
 "fmt"
)
type XCDataStu struct {
 Id   int    `json:"id"   xorm:"id"`
 Name string `json:"name"  xorm:"name"`
}
type XCDataStu1 struct {
 Id             int    `json:"id" xorm:"id"`
 Str1           string `json:"str1" xorm:"str1"`
 Db1            string `json:"db1" xorm:"db1"`
 Device_type    string `json:"Device_type" xorm:"Device_type"`
 DeviceTypeName string `json:"DeviceTypeName"`
}
type XCDataStuAll struct {//结构体嵌套
 XCDataStuinall  XCDataStu
 XCDataStu1inall XCDataStu1
}
func main() {

 xcData := []XCDataStu{
  XCDataStu{Id: 758, Name: "David758"},
  XCDataStu{Id: 759, Name: "David759"},
 }

 xcdataall := make([]XCDataStuAll, len(xcData))
 
 fmt.Println(len(xcData))
 fmt.Println(xcData[0])
 fmt.Println(xcData[1])
 i := 0
 for ; i < 2; i++ {
  xcdataall[i].XCDataStuinall.Id = xcData[i].Id
  xcdataall[i].XCDataStuinall.Name = xcData[i].Name
 }
 fmt.Println(xcdataall)
}

结构体切片：

可以直接声明时初始化，如程序中的1

可以用make，但是必须给定长度，否则不能使用下标进行赋值。

如程序中的2


 var xcdataall []XCDataStuAll
 for ; i < 2; i++ {
  xcdataall[i].XCDataStuinall.Id = xcData[i].Id
  xcdataall[i].XCDataStuinall.Name = xcData[i].Name
 }

程序编译没错，但是最后运行后会出现panic。。。

panic: runtime error: index out of range

补充：go遍历结构体(struct)字段对应的值,切片(slice),字典(map)

一、遍历结构体字段：

eg1:


package main
import (
    "fmt"
    "reflect"
)
type person struct {
    name string
    age  int
}
func main() {
    v := reflect.ValueOf(person{"steve", 30})
    count := v.NumField()
    for i := 0; i < count; i++ {
        f := v.Field(i)
        switch f.Kind() {
        case reflect.String:
            fmt.Println(f.String())
        case reflect.Int:
            fmt.Println(f.Int())
        }
    }
}

输出结果：

steve

30

eg2:


package main
import (
    "fmt"
    "reflect"
)
type NotknownType struct {
    s1, s2, s3 string
}
var secret interface{} = NotknownType{"Ada", "Go", "Oberon"}
func main() {
    value := reflect.ValueOf(secret)
    for i := 0; i < value.NumField(); i++ {
        fmt.Printf("Field %d: %v\n", i, value.Field(i))
    }
}

输出结果：

Field 0: Ada

Field 1: Go

Field 2: Oberon

二、遍历切片：

for range 结构


package main
import (
    "fmt"
)
func main(){
    slice := []string{"hello","world","hello","everyone!"}
    for k,val:=range slice{
        fmt.Printf("slice %d is :%s\n",k,val )
    }
}

输出结果：

slice 0 is :hello

slice 1 is :world

slice 2 is :hello

slice 3 is :everyone!

三、遍历map：


package main
import (
    "fmt"
)
func main() {
    m := make(map[string]string)
    m["1"] = "hello"
    m["2"] = "world"
    m["3"] = "go"
    m["4"] = "is"
    m["5"] = "cool"
    fmt.Printf("The corresponding relationship between key and value is:\n")
    for key, val := range m {
        fmt.Printf("%v===>%v\n", key, val)
    }
}

输出结果：

The corresponding relationship between key and value is:

1===>hello

2===>world

3===>go

4===>is

5===>cool

但是还有一个问题，上面的程序不做改动运行第二次，结果顺序就会改变，因为map遍历出来结果是无序的，这不好控制，也不利于业务逻辑;当业务依赖key次序时，需要引入“sort”包来解决随机化问题

代码如下：


package main
import (
    "fmt"
    "sort"
)
func main() {
    m := make(map[string]string)
    m["1"] = "hello"
    m["2"] = "world"
    m["3"] = "go"
    m["4"] = "is"
    m["5"] = "cool"
    sorted_keys := make([]string, 0)
    for k, _ := range m {
        sorted_keys = append(sorted_keys, k)
    }
    sort.Strings(sorted_keys)
    for _, k := range sorted_keys {
        fmt.Printf("%v=====>%v\n", k, m[k])
    }
}

输出结果是：