How to retrieve array of elements from array of structure in golang?

I am new to golang, and got stuck at this. I have an array of structure:

Users []struct {
   UserName string 
   Category string
   Age string
}

I want to retrieve all the UserName from this array of structure. So, output would be of type:

UserList []string 

I know the brute force method of using a loop to retrieve the elements manually and constructing an array from that. Is there any other way to do this?

Nope, loops are the way to go.

Here's a working example.

package main

import "fmt"

type User struct {
	UserName string
	Category string
	Age      int
}

type Users []User

func (u Users) NameList() []string {
	var list []string
	for _, user := range u {
		list = append(list, user.UserName)
	}
	return list
}

func main() {
	users := Users{
		User{UserName: "Bryan", Category: "Human", Age: 33},
		User{UserName: "Jane", Category: "Rocker", Age: 25},
		User{UserName: "Nancy", Category: "Mother", Age: 40},
		User{UserName: "Chris", Category: "Dude", Age: 19},
		User{UserName: "Martha", Category: "Cook", Age: 52},
	}

	UserList := users.NameList()

	fmt.Println(UserList)
}

No, go does not provide a lot of helper methods as python or ruby. So you have to iterate over the array of structures and populate your array.

No, not out of the box.

But, there is a Go package which has a lot of helper methods for this.
https://github.com/ahmetb/go-linq

If you import this you could use:

From(users).SelectT(func(u User) string { return u.UserName })

This package is based on C# .NET LINQ, which is perfect for this kind of operations.

Yes you can. Using https://github.com/szmcdull/glinq you can do:

package main

import (
	"fmt"

	"github.com/szmcdull/glinq/garray"
)

func main() {
	var users []struct {
		UserName string
		Category string
		Age      string
	}
	var userNames []string
	userNames = garray.MapI(users, func(i int) string { return users[i].UserName })
	fmt.Printf("%v\r\n", userNames)
}