The struct Data Type | Golang basics

Mahdi.Kh

September 21, 2026

We get familiar with the struct data type and learn how, similar to object-oriented programming languages, we can model objects using struct.

In Golang, the struct data type is a composite type used to group a set of related values under one name. These values, called a struct's fields, can have different data types.

Defining a struct

The general structure of a struct is as follows:

type name struct {
	field1 type1
	field2 type2
	field3 type3
}

For example, we can define a struct named Person that has two fields, Age and Name:

package main

import "fmt"

type Person struct {
	Name string
	Age  int
}

func main() {
	var x Person
	
	fmt.Println(x)
	fmt.Println(x.Name, x.Age)
	
	x.Name = "John Doe"
	x.Age = 45
	
	fmt.Println(x)
	fmt.Println(x.Name, x.Age)
}

In the example above, we first defined a struct named Person with two fields, Name and Age. We defined a variable named x of type Person, printed its zero value once, and then set and printed each field separately.

A struct's zero value is made up of the zero values of its fields. We can also assign the variable above as follows:

package main

import "fmt"

type Person struct {
	Name string
	Age  int
}

func main() {
	x := Person{
		Name: "John Doe",
		Age: 45,
	}

	fmt.Println(x)
	fmt.Println(x.Name, x.Age)
}

A struct can be created without giving it a name; this is called an anonymous struct. We just need to define the struct and assign it to a variable at the same time.

package main

import "fmt"

func main() {
	x := struct {
		Name string
		Age  int
	}{
		Name: "John Doe",
		Age:  45,
	}

	fmt.Println(x)
	fmt.Println(x.Name, x.Age)
}

Note that an anonymous struct isn't reusable, meaning if we want to define another variable with the same data type, we have to repeat the struct's structure again!

Using Nested Structs

There are two ways to use a struct in a nested fashion:

Having one or more fields of struct type
Placing a struct inside another struct without naming a field (embedding)

A struct can have several fields, and each of these fields can also be of struct type.

package main

import "fmt"

type UsersCollection struct {
	Items []User
	Count int
}

type User struct {
	Name string
	Age  int
}

func main() {
	user1 := User{
		Name: "John Doe",
		Age:  21,
	}

	user2 := User{
		Name: "James Bond",
		Age:  44,
	}

	collection := UsersCollection{
		Items: []User{
			user1, user2,
		},
		Count: 3,
	}

	fmt.Println(collection)
	fmt.Println(collection.Items)
	fmt.Println(collection.Count)

	for i, item := range collection.Items {
		fmt.Printf("%d- %s %d\n", i, item.Name, item.Age)
	}
}

Methods

In Go, you can add methods to any type you've defined, and structs are no different. The previous example can be rewritten using a method as follows:

#golang #go

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