Go语言中利用接口实现结构体切片的通用迭代与ID提取

type Foo struct {
    Id   int
    Name string
}

type Bar struct {
    Id    int
    Value float64
}

// 传统做法：为每种类型编写单独的函数
func getIdsFoo(foos []Foo) []int {
    ids := make([]int, 0, len(foos))
    for _, f := range foos {
        ids = append(ids, f.Id)
    }
    return ids
}

func getIdsBar(bars []Bar) []int {
    ids := make([]int, 0, len(bars))
    for _, b := range bars {
        ids = append(ids, b.Id)
    }
    return ids
}

type Identifiable interface {
    GetId() int
}

type Foo struct {
    Id   int
    Name string
}

// Foo 类型实现 Identifiable 接口的 GetId 方法
func (f Foo) GetId() int {
    return f.Id
}

type Bar struct {
    Id    int
    Value float64
}

// Bar 类型实现 Identifiable 接口的 GetId 方法
func (b Bar) GetId() int {
    return b.Id
}

func GatherIds(items []Identifiable) []int {
    ids := make([]int, 0, len(items)) // 预分配容量以优化性能
    for _, item := range items {
        ids = append(ids, item.GetId()) // 调用接口方法获取ID
    }
    return ids
}

package main

import "fmt"

// 定义Identifiable接口
type Identifiable interface {
    GetId() int
}

// Foo结构体及其GetId方法
type Foo struct {
    Id   int
    Name string
}

func (f Foo) GetId() int {
    return f.Id
}

// Bar结构体及其GetId方法
type Bar struct {
    Id    int
    Value float64
}

func (b Bar) GetId() int {
    return b.Id
}

// 通用ID收集函数
func GatherIds(items []Identifiable) []int {
    ids := make([]int, 0, len(items))
    for _, item := range items {
        ids = append(ids, item.GetId())
    }
    return ids
}

func main() {
    // 创建Foo结构体切片
    foos := []Foo{
        {Id: 101, Name: "Alpha"},
        {Id: 102, Name: "Beta"},
    }

    // 创建Bar结构体切片
    bars := []Bar{
        {Id: 201, Value: 3.14},
        {Id: 202, Value: 2.71},
    }

    // 将Foo切片转换为Identifiable接口切片
    // 注意：[]Foo不能直接赋值给[]Identifiable，需要逐个转换
    identifiableFoos := make([]Identifiable, len(foos))
    for i, f := range foos {
        identifiableFoos[i] = f
    }

    // 将Bar切片转换为Identifiable接口切片
    identifiableBars := make([]Identifiable, len(bars))
    for i, b := range bars {
        identifiableBars[i] = b
    }

    // 使用通用函数提取ID
    fooIds := GatherIds(identifiableFoos)
    barIds := GatherIds(identifiableBars)

    fmt.Printf("Foo IDs: %v\n", fooIds) // 输出: Foo IDs: [101 102]
    fmt.Printf("Bar IDs: %v\n", barIds) // 输出: Bar IDs: [201 202]

    // 也可以混合不同类型的Identifiable对象
    mixedItems := []Identifiable{
        Foo{Id: 301, Name: "Gamma"},
        Bar{Id: 401, Value: 1.618},
        Foo{Id: 302, Name: "Delta"},
    }
    mixedIds := GatherIds(mixedItems)
    fmt.Printf("Mixed IDs: %v\n", mixedIds) // 输出: Mixed IDs: [301 401 302]
}