Adding 2 array `type`s in Golang

Question

I have a type called EmployeeList which is just an array of Employee structs.

If I have to add/combine EmployeeList objects, I thought I could add them as follows

package main

import (
  "fmt"
)

type Employee struct {
  Id      int    `json:"id"`
  Name string    `json:"name"`
}

type EmployeeList []Employee

func main() {
  listA := EmployeeList{
    Employee{Id: 1, Name: "foo"},
    Employee{Id: 2, Name: "bar"},
  }

  listB := EmployeeList{
    Employee{Id: 3, Name: "baz"},
  }

  // Print the combined lists
  fmt.Println(append(listA, listB))
}

However the append is throwing an error:

./prog.go:24:21: cannot use listB (type EmployeeList) as type Employee in append

I get that it has to do with a mismatched / unexpected type, but I'm not sure how to add these two lists together?

Thanks!

2

Try `append(listA, listB...)` – jkr Feb 21 '20 at 15:55

score 1 · Answer 1 · answered Feb 21 '20 at 15:58

1

You cannot append an EmployeeList to an array of Employee. But because EmployeeList is defined as a list of Employee, you can unpack that array and append its elements to listA. You can unpack the array with ....

append(listA, listB...)

(refer to a similar answer https://stackoverflow.com/a/16248257/5666087)

answered Feb 21 '20 at 15:58

jkr

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That makes sense. Very similar to the splat operator `*args` in ruby I guess. Thank you! – user2490003 Feb 21 '20 at 16:04

Adding 2 array `type`s in Golang

1 Answers1