如何在Golang中初始化嵌套结构数组的值 [英] How to initialize values for nested struct array in golang

问题描述

我的结构

type Result struct {
   name   string
   Objects []struct {
       id int
   }
}

为此初始化值

func main() {
   var r Result;
   r.name  = "Vanaraj";
   r.Objects[0].id = 10;
   fmt.Println(r)
}

我收到此错误.紧急:运行时错误:索引超出范围"

I got this error. "panic: runtime error: index out of range"

该如何解决?

推荐答案

首先，我要说的是，为您的结构定义类型是更习惯的做法，而不管该结构多么简单.例如:

Firstly, I'd say it's more idiomatic to define a type for your struct, regardless of how simple the struct is. For example:

type MyStruct struct {
    MyField int
}

这意味着将您的 Result 结构更改如下:

This would mean changing your Result struct to be as follows:

type Result struct {
    name   string
    Objects []MyStruct
}

程序出现恐慌的原因是，您试图访问内存中尚未分配的区域( Object s数组中的一项).

The reason your program panics is because you're trying to access an area in memory (an item in your Objects array) that hasn't been allocated yet.

对于结构数组，这需要使用 make 完成.

For arrays of structs, this needs to be done with make.

r.Objects = make([]MyStruct, 0)

然后，为了安全地添加到数组中，最好实例化单个 MyStruct ，即

Then, in order to add to your array safely, you're better off instantiating an individual MyStruct, i.e.

ms := MyStruct{
    MyField: 10,
}

然后将其附加到您的 r.Objects 数组

And then appending this to your r.Objects array

r.Objects = append(r.Objects, ms)

有关 make 的更多信息，请参见文档

For more information about make, see the docs

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