What is an empty interface?

An empty interface in Go is an interface without methods, written as interface{}. It can hold a value of any type, since all types implement the empty interface.

This is convenient for storing data of unknown type or creating generic functions. However, when using the empty interface, it is often necessary to perform type assertion or type switch to work with a specific type.

Example:

var x interface{}
 x = 42
fmt.Println(x) // outputs 42

// To get a specific type:
if val, ok := x.(int); ok {
    fmt.Println("Integer:", val)
}