遍历切片slice，结构体struct，映射map，interface{}的属性和值

1 前言

说明：interface{}必须是前三者类型

2 代码

/**
 * @Author: FB
 * @Description:
 * @File:  testOutput.go
 * @Version: 1.0.0
 * @Date: 2019/6/3 10:38
 */

package main

import (
   "reflect"
   "fmt"
)

type NotknownType struct {
   s1, s2, s3 string
}

type NotknownType2 struct {
   S1, S2, S3 string
}

//只输出值且属性名小写
func output11(obj  NotknownType){
   value := reflect.ValueOf(obj)
   for i := 0; i < value.NumField(); i++ {
      fmt.Printf("Field %d: %v\n", i, value.Field(i))
   }
}

//只输出属性和值且属性名小写
func output12(obj  NotknownType){
   value := reflect.ValueOf(obj)
   t := reflect.TypeOf(obj)
   for i := 0; i < t.NumField(); i++ {
      fmt.Println(t.Field(i).Name, "->", value.Field(i).Interface())
   }
}
//只输出值且属性名大写
func output21(obj  NotknownType2){
   value := reflect.ValueOf(obj)
   for i := 0; i < value.NumField(); i++ {
      fmt.Printf("Field %d: %v\n", i, value.Field(i))
   }
}
//只输出属性和值且属性名大写
func output22(obj  NotknownType2){
   value := reflect.ValueOf(obj)
   t := reflect.TypeOf(obj)
   for i := 0; i < t.NumField(); i++ {
      fmt.Println(t.Field(i).Name, "->", value.Field(i).Interface())
   }
}

//只输出属性和值且属性名大写
func output221(obj  NotknownType2){
		fmt.Printf("%+v",obj)
		fmt.Println()
}

//以下是参数为interface{}，和上面四个其它一一对应
func output110(obj  interface{}){
   value := reflect.ValueOf(obj)
   for i := 0; i < value.NumField(); i++ {
      fmt.Printf("Field %d: %v\n", i, value.Field(i))
   }
}

func output120(obj  interface{}){
   value := reflect.ValueOf(obj)
   t := reflect.TypeOf(obj)
   for i := 0; i < t.NumField(); i++ {
      fmt.Println(t.Field(i).Name, "->", value.Field(i).Interface())
   }
}

func output210(obj  interface{}){
   value := reflect.ValueOf(obj)
   for i := 0; i < value.NumField(); i++ {
      fmt.Printf("Field %d: %v\n", i, value.Field(i))
   }
}

func output220(obj  interface{}){
   value := reflect.ValueOf(obj)
   t := reflect.TypeOf(obj)
   for i := 0; i < t.NumField(); i++ {
      fmt.Println(t.Field(i).Name, "->", value.Field(i).Interface())
   }
}

func main() {

   var secret = NotknownType{"Ada", "Go", "Oberon"}
   var secret2  = NotknownType2{"Ada", "Go", "Oberon"}

   var map1 = map[string]string{"s1":"Ada", "s2":"Go", "s3":"Oberon"}
   var slice1 = []string{"Ada", "Go", "Oberon"}

   var obj interface{} = NotknownType{"Ada", "Go", "Oberon"}
   var obj2 interface{} = NotknownType2{"Ada", "Go", "Oberon"}

   //参数是struct
   fmt.Println("output11只输出值且属性名小写")
   output11(secret)
   //报错panic: reflect.Value.Interface: cannot return value obtained from unexported field or method，因为属性是小写，反射拿不到值
   //fmt.Println("output12")
   //output12(secret)
   fmt.Println("output21只输出值且属性名大写")
   output21(secret2)
   fmt.Println("output22只输出属性和值且属性名大写")
   output22(secret2)

        fmt.Println()
	fmt.Println("output221")
	output221(secret)
	fmt.Println("output222")
	output222(secret2)
	fmt.Println()

   //参数是interface{}
   fmt.Println("output110只输出值且属性名小写，参数为interface{}")
   output110(obj)
   //报错panic: reflect.Value.Interface: cannot return value obtained from unexported field or method，因为属性是小写，反射拿不到值
   //fmt.Println("output120")
   //output120(obj)
   fmt.Println("output210只输出值且属性名大写，参数为interface{}")
   output210(obj2)
   fmt.Println("output220只输出属性和值且属性名大写，参数为interface{}")
   output220(obj2)

   //报错panic: reflect: NumField of non-struct type
   //output220(map1)
   fmt.Println("output220 只输出属性和值且属性名大写，输入为struct属性大写")
   output220(secret2)

   fmt.Println("遍历map，输出键和值")
   //输出map键和值
   for k,v := range map1{
      fmt.Println(k,"->",v)
   }

   fmt.Println("遍历slice，输出值")
   //输出map键和值
   for i, v := range slice1{
      fmt.Println(i, "->", v)
   }

}

输出：

output11只输出值且属性名小写
Field 0: Ada
Field 1: Go
Field 2: Oberon
output21只输出值且属性名大写
Field 0: Ada
Field 1: Go
Field 2: Oberon
output22只输出属性和值且属性名大写
S1 -> Ada
S2 -> Go
S3 -> Oberon

output221
{s1:Ada s2:Go s3:Oberon}
output222
{S1:Ada S2:Go S3:Oberon}

output110只输出值且属性名小写，参数为interface{}
Field 0: Ada
Field 1: Go
Field 2: Oberon
output210只输出值且属性名大写，参数为interface{}
Field 0: Ada
Field 1: Go
Field 2: Oberon
output220只输出属性和值且属性名大写，参数为interface{}
S1 -> Ada
S2 -> Go
S3 -> Oberon
output220 只输出属性和值且属性名大写，输入为struct属性大写
S1 -> Ada
S2 -> Go
S3 -> Oberon
遍历map，输出键和值
s1 -> Ada
s2 -> Go
s3 -> Oberon
遍历slice，输出值
0 -> Ada
1 -> Go
2 -> Oberon

Debugger finished with exit code 0