In fact, you can define a method on any type you define in your package, not just structs.
You cannot define a method on a type from another package, or on a basic type.
package main import ( "fmt" "math" ) type MyFloat float64 func (f MyFloat) Abs() float64 { if f < 0 { return float64(-f) } return float64(f) } func main() { fmt.Println(math.Sqrt2) f := MyFloat(-math.Sqrt2) fmt.Println(f.Abs()) }
很像OC中的类别
A Tour of Go Methods continued
原文：http://www.cnblogs.com/ghgyj/p/4057602.html