Methods in Go

Language

Version: 1.6

Functions

Methods are functions which have a receiver argument (belonging to a predefined type).

Syntax

func (variableName typeName) methodName(paramName paramType) (returnVarName returnType) {
    //some operation, usually on fields of the type
)

//methods are called on the variable of its type
variableName := typeName{ values for struct }
variableName.methodName(params)

Notes

Methods are typically used to emulate class-like behavior on struct types. Methods do not have to receive a struct type.

Pointers can also be receiving types for methods.

Methods behave exactly the same as functions.

Example

package main

import "fmt"

type Degrees struct {
    angle float64
}

//method
func (deg Degrees) toRad() float64 {
    return deg.angle * (3.14 / 180.0)
}

func main() {
    angle := Degrees { 90.0 }
    fmt.Println("Angle, in radians: ", angle.toRad())
}