映射与字符串键和字符串或切片值？

问题描述：

Newbee warning.

Can I make a map with a string key and "anything" as a value? The goal is to have a map of configuration data. This data can be either a single string (or boolean value or integer, but restricting this to a string is fine), or it can be an array of strings. Example: I'd like to store these items:

levels = 3
extra-directories = ["foo","bar","baz"]

The first option is always a single value (a string would be OK for me). The second option is zero or more values.

The goal is to have a single map where I can store these values and when looking at the map, I could use switch x.(type) to find out what the value is.

Newbee警告。 p>

我可以使用字符串键制作地图吗？ “什么”作为价值？目标是拥有配置数据图。该数据可以是单个字符串（或布尔值或整数，但是将其限制为字符串是可以的），也可以是字符串数组。示例：我想存储以下项目： p>

  levels = 3 
extra-directories = [“ foo”，“ bar”，“ baz”] 
   code>  pre> 
 
 第一个选项始终是单个值（字符串对我来说是可以的）。 第二个选项是零个或多个值。   p> 
 
 
目标是制作一张可以存储这些值的地图，当查看地图时，可以使用 switch x。（type） code>查找 找出值是什么。 p> 
  div>

答

interface{} is a type that accepts any type.

conf := map[string] interface{} {
    "name": "Default",
    "server": "localhost",
    "timeout": 120,
}

conf["name"] is an interface{} not a string, and conf["timeout"] is an interface{} not an int. You can pass conf["name"] to functions that take interface{} like fmt.Println, but you can't pass it to functions that take string like strings.ToUpper, unless you know that the interface{}'s value is a string (which you do) and assert it's type:

name := conf["name"].(string)
fmt.Println("name:", strings.ToUpper(name))
server := conf["server"].(string)
fmt.Println("server:", strings.ToUpper(server))
timeout := conf["timeout"].(int)
fmt.Println("timeout in minutes:",  timeout / 60)

Another solution that might fit your problem is to define a struct:

type Config struct {
    Name string
    Server string
    Timeout int
}

Create configuration:

conf := Config{
    Name: "Default",
    Server: "localhost",
    Tiemout: 60,
}

Access configuration:

fmt.Println("name:", strings.ToUpper(conf.Name))
fmt.Println("server:", strings.ToUpper(cnf.Server))
fmt.Println("timeout in minutes:",  conf.Timeout / 60)

答

Yes, you can do that using a map having type map[string]interface{}.

映射与字符串键和字符串或切片值？

相关推荐