learngo/interfaces/06-empty-interface/empty/main.go

// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//
// For more tutorials  : https://learngoprogramming.com
// In-person training  : https://www.linkedin.com/in/inancgumus/
// Follow me on twitter: https://twitter.com/inancgumus

package main

import "fmt"

func main() {
	// Let's create a variable using the empty interface type.
	var any interface{}

	// The variable can accept any type of value.
	any = []int{1, 2, 3}
	any = map[int]bool{1: true, 2: false}
	any = "hello"
	any = 3

	// You can't multiply the last number.
	// Reason: `any` is an `interface{}`, it's not a number.
	// any = any * 2
	// any = int(any) * 2

	any = any.(int) * 2
	fmt.Println(any)
}