在地图中分配给匿名结构值 [英] Assign to anonymous struct value in map

问题描述

我正在使用go 1.3.

I am using go 1.3.

如何访问地图的匿名结构ValueType的字段?

How can I access the fields of the anonymous struct ValueType of the map ?

package main

import "fmt"

type Words map[string]struct{
    pos   int
    n     int
}

func main() {
    w := make(Words)
    w["abc"].pos = 5 // cannot assign

    fmt.Println(w)
}

推荐答案

您需要为键分配一个值(您的结构):

You need to assign a value (your struct) to your key:

type S struct {
    pos int
    n   int
}
type Words map[string]S

func main() {
    w := make(Words)
    s := S{pos: 1, n: 2}
    w["abc"] = s 
    fmt.Println(w)
}

请参见以下 play.golang.org 示例.

See this play.golang.org example.

输出:

map[abc:{1 2}]

更多信息，请参见"实际使用地图".

See more at "Go maps in action".

然后，您可以检索您的值并分配:

Then you can retrieve your value and assign:

sbis := w["abc"]
sbis.pos = 11
fmt.Println(sbis)

输出:

{11 2}

---

在他的示例中，

---

In his example, OneOfOne proposes a getter in order to assign pos quicker, but creating if needed the right value (that is an instance of the struct):

func (w Words) get(s string) (p *ps) {
    if p = w[s]; p == nil {
        p = &ps{}
        w[s] = p
    }
    return
}

这允许:

w := Words{}
w.get("abc").pos = 10

这篇关于在地图中分配给匿名结构值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！