What is the difference between interfaces in the Go language compared to interfaces in other programming languages?

In Go, interfaces are different because they are implicit — a type does not need to explicitly declare that it implements an interface. If a type contains all the methods of an interface, it is automatically considered to implement it.

This differs from many other languages where you need to explicitly declare that a class or type implements an interface.

Example:

package main
import "fmt"

type Reader interface {
    Read(p []byte) (n int, err error)
}

type File struct {}

func (f File) Read(p []byte) (n int, err error) {
    // implementation
    return 0, nil
}

func main() {
    var r Reader
    var f File
    r = f // File automatically implements Reader
    fmt.Println(r)
}