dqy27359 2017-01-05 08:43
浏览 405
已采纳

如何使Go将枚举字段打印为字符串?

You print an enum that implements Stringer using "%v", it will print its string value. If you declare the same enum inside a struct and print the struct using "%v", it will print enum's numeric value. Is there a way to print the string value of a enum field?

Sample (https://play.golang.org/p/AP_tzzAZMI):

package main

import (
    "fmt"
)

type MyEnum int

const (
    Foo MyEnum = 1
    Bar MyEnum = 2
)

func (e MyEnum) String() string {
    switch e {
    case Foo:
        return "Foo"
    case Bar:
        return "Bar"
    default:
        return fmt.Sprintf("%d", int(e))
    }
}

type MyStruct struct {
    field MyEnum
}

func main() {
    info := &MyStruct{
        field: MyEnum(1),
    }
    fmt.Printf("%v
", MyEnum(1))
    fmt.Printf("%v
", info)
    fmt.Printf("%+v
", info)
    fmt.Printf("%#v
", info)
}

Prints:

Foo
&{1}
&{field:1}
&main.MyStruct{field:1}
  • 写回答

1条回答 默认 最新

  • duanlu1922 2017-01-05 08:51
    关注

    You need to make the field exported,ie you may declare the struct as

    type MyStruct struct {
        Field MyEnum
    }
    

    Here is a sample program with exported and unexported fields

    Code

    package main
    
    import (
        "fmt"
    )
    
    type MyEnum int
    
    const (
        Foo MyEnum = 1
        Bar MyEnum = 2
    )
    
    func (e MyEnum) String() string {
        switch e {
        case Foo:
            return "Foo"
        case Bar:
            return "Bar"
        default:
            return fmt.Sprintf("%d", int(e))
        }
    }
    
    type MyStruct struct {
        Field1 MyEnum
        field2 MyEnum
    }
    
    func main() {
        info := &MyStruct{
            Field1: MyEnum(1),
            field2: MyEnum(2),
        }
        fmt.Printf("%v
    ", MyEnum(1))
        fmt.Printf("%v
    ", info)
        fmt.Printf("%+v
    ", info)
        fmt.Printf("%#v
    ", info)
    }
    

    Output

    Foo
    &{Foo 2}
    &{Field1:Foo field2:2}
    &main.MyStruct{Field1:1, field2:2}
    

    Here is play link : https://play.golang.org/p/7knxM4KbLh

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 python天天向上类似问题,但没有清零
  • ¥30 3天&7天&&15天&销量如何统计同一行
  • ¥30 帮我写一段可以读取LD2450数据并计算距离的Arduino代码
  • ¥15 C#调用python代码(python带有库)
  • ¥15 矩阵加法的规则是两个矩阵中对应位置的数的绝对值进行加和
  • ¥15 活动选择题。最多可以参加几个项目?
  • ¥15 飞机曲面部件如机翼,壁板等具体的孔位模型
  • ¥15 vs2019中数据导出问题
  • ¥20 云服务Linux系统TCP-MSS值修改?
  • ¥20 关于#单片机#的问题:项目:使用模拟iic与ov2640通讯环境:F407问题:读取的ID号总是0xff,自己调了调发现在读从机数据时,SDA线上并未有信号变化(语言-c语言)