Accessing struct fields in Go

Introduction

Structs group related data together. Accessing struct fields lets you get or change specific pieces of that data.

You want to store information about a person, like name and age, and then read or update those details.

You have a product with price and quantity, and you need to calculate total cost using those fields.

You want to organize settings for a game or app and access each setting separately.

You receive data from a sensor and want to read specific measurements stored in a struct.

Syntax

Go

structVariable.fieldName

Use the dot . to get or set a field inside a struct variable.

Field names start with a capital letter if you want to access them from other packages.

Examples

Set and print fields of a struct variable.

Go

type Person struct {
    Name string
    Age  int
}

var p Person
p.Name = "Alice"
p.Age = 30
fmt.Println(p.Name, p.Age)

Create a struct with values and access fields to print them.

Go

p := Person{Name: "Bob", Age: 25}
fmt.Println(p.Name)
fmt.Println(p.Age)

Change one field after creating the struct.

Go

type Point struct {
    X, Y int
}

pt := Point{X: 10, Y: 20}
pt.X = 15
fmt.Println(pt.X, pt.Y)

Sample Program

This program creates a Car struct, prints its fields, updates the Year field, and prints it again.

Go

package main

import "fmt"

type Car struct {
    Brand string
    Year  int
}

func main() {
    myCar := Car{Brand: "Toyota", Year: 2020}
    fmt.Println("Brand:", myCar.Brand)
    fmt.Println("Year:", myCar.Year)

    // Update the year
    myCar.Year = 2022
    fmt.Println("Updated Year:", myCar.Year)
}

Important Notes

If you have a pointer to a struct, you can access fields with the same dot syntax, Go handles the pointer automatically.

Trying to access a field that does not exist will cause a compile error.

Summary

Use structVariable.fieldName to access or change a struct's field.

Fields hold the data inside a struct and can be read or updated.

Structs help organize related data in one place.