Golang动态创建Struct的成员 [英] Golang dynamic creating member of Struct

问题描述

我对Golang相当陌生。我知道Golang中有Struct。但是对于我所知道的，你必须定义struct

 类型Circle结构{
x，y，r float64 
 
  

我想知道如何声明一个不存在于Struct中的新变量

  circle：= new（Cirlce）
 circle.color =black
  

Thx提前。

解决方案

您需要使用映射（类型为 map [string] interface {} ）来处理动态JSON。这是一个创建新地图的例子：

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ bm：= map [string] interface { } {
key：value，
}

//动态添加一个子映射
m [sub] = map [string] interface {} {
deepKey：deepValue，
}

解组JSON到一个映射如下所示：

  var f interface {} 
 err：= json.Unmarshal（b，& amp ; f）
  

上面的代码会在 f ，结构类似于：

  f = map [string] interface {} {
 姓名：星期三，
年龄：6，
父母：[]界面{} {
戈麦斯，
Morticia，
 
 
 
 
 $ b 
你将需要使用一个类型断言来访问它， 
 
 
  m：= f。（map [string] interface {}）
  
您也会需要在您从地图中拉出的每个项目上使用断言或类型开关。处理非结构化JSON是一件麻烦事。
 
 
 
更多信息： 
 
 
 
 
  https://blog.golang.org/json-and-go  
 
 
  https://godoc.org/encoding/json#Unmarshal  
 
 
 
I am fairly new to Golang. I know there is Struct in Golang. But for all I know, you have to define struct 
type Circle struct{
    x,y,r float64
}
I am wondering how you can declare a new variable that doesn't exist in the Struct
circle := new(Cirlce)
circle.color = "black"
Thx in advance.
解决方案
You will need to use a map (of type map[string]interface{}) to work with dynamic JSON.  Here is an example of creating a new map:
// Initial declaration
m := map[string]interface{}{
    "key": "value",
}

// Dynamically add a sub-map
m["sub"] = map[string]interface{}{
    "deepKey": "deepValue",
}
Unmarshalling JSON into a map looks like:
var f interface{}
err := json.Unmarshal(b, &f)
The code above would leave you with a map in f, with a structure resembling:
f = map[string]interface{}{
    "Name": "Wednesday",
    "Age":  6,
    "Parents": []interface{}{
        "Gomez",
        "Morticia",
    },
}
You will need to use a type assertion to access it, otherwise Go won't know it's a map:
m := f.(map[string]interface{})
You will also need to use assertions or type switches on each item you pull out of the map.  Dealing with unstructured JSON is a hassle.

More information:


https://blog.golang.org/json-and-go
https://godoc.org/encoding/json#Unmarshal


                        
这篇关于Golang动态创建Struct的成员的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！