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) }
A Tour of Go Short variable declarations
原文：http://www.cnblogs.com/ghgyj/p/4052629.html