笑故挽风 2013-11-27 02:41 采纳率: 100%
浏览 260
已采纳

围棋中的零点侦测

I see a lot of code in Go to detect nil, like this:

if err != nil { 
    // handle the error    
}

however, I have a struct like this:

type Config struct {
    host string  
    port float64
}

and config is an instance of Config, when I do:

if config == nil {
}

there is compile error, saying: cannot convert nil to type Config

转载于:https://stackoverflow.com/questions/20240179/nil-detection-in-go

  • 写回答

5条回答 默认 最新

  • 狐狸.fox 2013-11-27 02:47
    关注

    The compiler is pointing the error to you, you're comparing a structure instance and nil. They're not of the same type so it considers it as an invalid comparison and yells at you.

    What you want to do here is to compare a pointer to your config instance to nil, which is a valid comparison. To do that you can either use the golang new builtin, or initialize a pointer to it:

    config := new(Config) // not nil
    

    or

    config := &Config{host: myhost.com, port: 22} // not nil
    

    or

    var config *Config // nil
    

    Then you'll be able to check if

    if config == nil {
        // then
    }
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(4条)
编辑
预览

报告相同问题?

悬赏问题

  • ¥15 DBIF_REPO_SQL_ERROR
  • ¥15 根据历年月数据,用Stata预测未来六个月汇率
  • ¥15 DevEco studio开发工具 真机联调找不到手机设备
  • ¥15 请教前后端分离的问题
  • ¥100 冷钱包突然失效,急寻解决方案
  • ¥15 下载honeyd时报错 configure: error: you need to instal a more recent version of libdnet
  • ¥15 距离软磁铁一定距离的磁感应强度大小怎么求
  • ¥15 霍尔传感器hmc5883l的xyz轴输出和该点的磁感应强度大小的关系是什么
  • ¥15 vscode开发micropython,import模块出现异常
  • ¥20 Excel数据自动录入表单并提交