英文:
structure pointer field on a map in Golang
问题
我想在地图中包含不同结构的指针字段，如下所示。（当然，下面的代码是无效的）
type StructA struct {
}
type StructB struct {
}
mymap := map[string]*struct{}{
"StructA": &StructA{},
"StructB": &StructB{},
}
请注意，你需要使用&符号来获取结构体的指针，并在每个结构体后面加上{}来创建实例。
英文:
I want to include different structure pointer fields in the map as shown below. (Of course the code below doesnt work)
type StructA struct {
}
type StructB struct {
}
mymap := map[string]*struct{}{
"StructA": StructA,
"StructB": StructB,
}
答案1
得分: 2
如@icza所说，映射的元素类型必须是特定类型。但是，这可以是一个可以存储不同类型对象的接口。类型any（interface{}的别名）在某种程度上类似于指针（尽管它还存储类型信息），因此你可以这样做：
mymap := map[string]interface{}{
"StructA": StructA{},
"StructB": StructB{},
}
为了更安全一些，你可以限制可以添加到映射中的类型只能是这两个结构体。为此，你需要一个指定两个结构体类型都实现的函数的接口。
type (
Common interface{ ImplementsCommon() }
A struct{}
B struct{}
)
func (A) ImplementsCommon() {}
func (B) ImplementsCommon() {}
mymap := map[string]Common{
"A": A{},
"B": B{},
}
在Go Playground上试一试。
英文:
As @icza said the element type of a map must be a specific type. But this could be an interface that can store an object of different types. The type any (an alias for interface{} is in some ways like a pointer (though it also stores type info), so you could just do:
mymap := map[string]inteface{}{
"StructA": StructA{},
"StructB": StructB{},
}
To be a little safer you can restrict the types that can be added to the map to just the two structs. To do this you need an interface which specifies a function that both the struct types implement.
type (
Common interface{ ImplementsCommon() }
A struct{}
B struct{}
)
func (A) ImplementsCommon() {}
func (B) ImplementsCommon() {}
mymap := map[string]Common{
"A": A{},
"B": B{},
}
Try it on the Go Playground
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