在Go中传递任意切片

Question

I'm writing a function that retrieves arbitrary data from a database, and returns a slice of structs with the results. The data structure is defined by the user in an ItemFactory. The user then implements methods on the factory, that create empty structs:

func (t Example) GenerateEmptyItem() interface{} {
    return &Example{}
}

I am trying to do the same for slices of Example . I need to be able to use whatever is returned, to call functions such as len() , while at the same time, keeping it generic as to allow it to be returned by "generic" functions.

I can't simply have something like this, as the underlying data allocation for a slice of interfaces is different from a slice of Examples:

func (t Country) GenerateEmptyItems() []interface{} {
    return []Country{} //Error
}

Is it possible to use a pointer to a slice, such as &[]Example{} and pass it as an interface{} , and then still be able to use it as a slice? Or am I going about this wrong?.Remember, I don't know the type of the data at compile-time, so I can't simply cast.

I appreciate any help. Let me know if I can clarify anything.

Answer 1

You can't quite do this directly.

You can use reflection , however this isn't a great solution. The normal way is to have an interface type defined that lets you interact with all the data in the same way. A good example of this is the sort package.