The zero value of a slice is nil.
A nil slice has a length and capacity of 0.
(To learn more about slices, read the Slices: usage and internalsarticle.)
package main import "fmt" func main() { var z []int fmt.Println(z, len(z), cap(z)) if z == nil { fmt.Println("nil!") } }
原文：http://www.cnblogs.com/ghgyj/p/4053321.html