在Golang中深度复制地图 [英] Deep copying maps in Golang

问题描述

据我了解，地图是Go中的参考类型.因此，作业将进行浅表复制.我计划在golang中进行Maps的递归深层复制.递归的，因为我正在处理一个包含JSON的未编组内容的映射.

From what I understand, maps are reference types in Go. So assignment will do shallow copy. I plan to do a recursive deep copy of Maps in golang. Recursive because I am dealing with a map that holds the unmarshalled contents of a JSON.

func deepCopyJSON(src map[string]interface{}, dest *map[string]interface{}) error {
    if src == nil || dest == nil {
        return errors.New("src/dest is nil. You cannot insert to a nil map")
    }
    for key, value := range src {
        if reflect.TypeOf(value).String() != jsonType {
            (*dest)[key] = value
        } else {
            (*dest)[key] = make(map[string]int)
//Suspect code below causes the error.
            deepCopyJSON(value.(map[string]interface{}), &(((*dest)[key]).(map[string]interface{})))
        }
    }
    return nil
}

错误:不能使用(* dest)[key]的地址.(map [string] interface {}) 我该如何解决?还有其他深层地图的方法吗?

The Error: cannot take the address of (*dest)[key].(map[string]interface {}) How do I get around this? Are there other ways to deep maps?

我在golang的map的内部结构上入门，也很有用.

I primer on the internals of map in golang, will also be useful.

推荐答案

func deepCopyJSON(src map[string]interface{}, dest map[string]interface{}) error {
    if src == nil {
        return errors.New("src is nil. You cannot read from a nil map")
    }
    if dest == nil {
        return errors.New("dest is nil. You cannot insert to a nil map")
    }
    jsonStr, err := json.Marshal(src)
    if err != nil {
        return err
    }
    err = json.Unmarshal(jsonStr, &dest)
    if err != nil {
        return err
    }
    return nil
}

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