A Tour of Go Short variable declarations

Inside a function, the := short assignment statement can be used in place of a var declaration with implicit type.

Outside a function, every construct begins with a keyword (var, func, and so on) and the := construct is not available.

package main 

import "fmt"

var k int = 3
var k2 = 3
//k3 := 4 //non-declaration statement outside function body
func main() {
    var i, j int = 1, 2
    k := 3
    c, python, java := true, false, "no!"
    fmt.Println(i, j, k, c, python, java)
}