Go methods

#go #beginners

Go does not have classes or object orientated programming in the traditional sense. But you can define methods on types.

In Go, a method is a function with a special receiver argument. For example, we define two methods like that (getX and getY):

package main

import (
    "fmt"
)

type Coordinate struct {
    X, Y float64
}

func (v Coordinate) getX() float64 {
    return v.X
}

func (v Coordinate) getY() float64 {
    return v.Y
}

func main() {
    v := Coordinate{3, 4}
    fmt.Println(v.getX())
    fmt.Println(v.getY())
}

This outputs the x and y values of the struct.

3
4

Program exited.

So on a programming level with Go, you might not miss OOP as structs work just fine and you can apply methods.

A method can do more than just return a value. In the example below, the method Abs has a receiver of type Vertex named v.

package main

import (
    "fmt"
    "math"
)

type Vertex struct {
    X, Y float64
}

func (v Vertex) Abs() float64 {
    return math.Sqrt(v.X*v.X + v.Y*v.Y)
}

func main() {
    v := Vertex{3, 4}
    fmt.Println(v.Abs())
}