The Empty interface in Golang

An empty interface can be used to hold any data and it can be a useful parameter since it can work with any type.

The interface type that specifies zero methods is known as the empty interface:

interface{}

Empty interfaces are used by code that handles values of unknown type. For example, fmt.Print takes any number of arguments of type interface{}.

package main
import "fmt"
func main() {
 var i interface{}
 describe(i)
i = 42
 describe(i)
i = "hello"
 describe(i)
}
func describe(i interface{}) {
 fmt.Printf("(%v, %T)\n", i, i)
}

Output:

(<nil>, <nil>)
(42, int)
(hello, string)

As we can see in the above example describe() method is called for different types(int and string). For more details of the internal implementation of interfaces refer to https://research.swtch.com/interfaces.