Adding Filter method to List

list_filter.go

package main

import "container/list"

type MyList struct {
  *list.List
}

func (l *MyList) Filter(f func(interface{}) bool) *MyList {
  nl := &MyList{list.New()}
  for e := l.Front(); e != nil; e = e.Next() {
    v := e.Value
    if f(v) {
      nl.PushBack(v)
    }
  }
  return nl
}