Golang：通过反射获取具名字段的底层结构体值

package main

import (
    "fmt"
    "reflect"
)

type Dice struct {
    In int
}

type SliceNDice struct {
    Unknown []Dice
}

func main() {
    structure := SliceNDice{make([]Dice, 10)}

    // 获取结构体的反射值，并获取"Unknown"字段
    refValue := reflect.ValueOf(&structure).Elem().FieldByName("Unknown")

    // 尝试直接迭代 reflect.Value 类型的切片
    // slice := refValue.Slice(0, refValue.Len())
    // for i,v := range slice { // 编译错误：cannot range over slice (type reflect.Value)
    //     fmt.Printf("%v %v\n", i, v.In) // 编译错误：v.In undefined (type reflect.Value has no field or method In)
    // }

    // 通过索引迭代，但每个元素仍是 reflect.Value
    for i := 0; i < refValue.Len(); i++ {
        v := refValue.Index(i)
        // v.In undefined (type reflect.Value has no field or method In)
        // 仍然无法直接访问 v.In
        fmt.Printf("Element %v is reflect.Value of kind %v\n", i, v.Kind())
    }
}

package main

import (
    "fmt"
    "reflect"
)

type Dice struct {
    In int
}

type SliceNDice struct {
    Unknown []Dice
}

func main() {
    // 初始化结构体，并填充一些数据以便演示
    structure := SliceNDice{Unknown: make([]Dice, 5)}
    for i := 0; i < 5; i++ {
        structure.Unknown[i].In = i * 10
    }

    // 1. 获取结构体的反射值，并获取"Unknown"字段
    // Elem() 用于获取指针指向的实际值
    refValue := reflect.ValueOf(&structure).Elem().FieldByName("Unknown")

    // 2. 使用 Interface() 获取底层值，并进行类型断言
    // 确保你知道字段的实际类型，这里是 []Dice
    if refValue.Kind() == reflect.Slice { // 检查是否是切片类型
        // 将 reflect.Value 转换为 interface{}，然后断言为 []Dice
        slice, ok := refValue.Interface().([]Dice)
        if !ok {
            fmt.Println("Type assertion failed: field 'Unknown' is not []Dice")
            return
        }

        // 现在 slice 是一个 []Dice 类型的切片，可以进行常规迭代和访问
        fmt.Println("Successfully asserted to []Dice. Iterating:")
        for i, v := range slice {
            fmt.Printf("Index: %v, Value.In: %v\n", i, v.In)
        }
    } else {
        fmt.Printf("Field 'Unknown' is not a slice, but a %v\n", refValue.Kind())
    }
}

Successfully asserted to []Dice. Iterating:
Index: 0, Value.In: 0
Index: 1, Value.In: 10
Index: 2, Value.In: 20
Index: 3, Value.In: 30
Index: 4, Value.In: 40