Golang：从列表元素获取值

Question

http://play.golang.org/p/TE02wFCprM

I am getting error panic when I try to get the value from a struct which is from list.

   fmt.Println(A_elem.Value.(Player).year) //3000

What I did is make a list and add structures into the list. When I retrieve the element from the list, it is in interface type. But still if I print out the whole interface type value, it has structure values in it. So I tried to get one value of structure but getting the panic error.

This line is working well.

   fmt.Println(A_elem.Value)                    //&{dddd 3000}

code is here

package main

import (
  "container/list"
  "fmt"
)

func main() {

  type Player struct {
    name      string
    year   int
  }
  A := new(Player)
  A.name = "aaaa"
  A.year = 1990

  B := new(Player)
  B.name = "eeee"
  B.year = 2000

  C := new(Player)
  C.name = "dddd"
  C.year = 3000

  play := list.New()
  play.PushBack(A)
  play.PushBack(B)
  play.PushBack(C)

  A_elem := play.Back()

  //A_elem.Value is type Player struct
  fmt.Println(A_elem.Value)                    //&{dddd 3000}
  fmt.Println(A_elem.Value.(Player).year) //3000
}

I want to save structures in the list and be able to retrieve the specific values from one of the structures that are saved in list.

How could I do it?

Thanks in advance.

Answer 1

The precise problem is that you tried to do a bad type assertion.

The list holds *Player, but you tired to type assert that it is a plain Player struct.

Playground link with this fixed.