Deeply understand the difference between methods and functions in Go language

In the Go language, methods are associated with specific types. The method name has a receiver parameter and is used to operate instances of a specific type, while functions are independent code blocks that are not associated with any type and receive variables in the form of ordinary parameters. or value.

The difference between methods and functions in Go language

Introduction

In Go In the language, methods and functions are two important concepts in the code, and understanding the difference between them is crucial to writing effective and maintainable code. This article will delve into the differences between methods and functions and illustrate them with practical examples.

Methods

Methods are functions associated with a type that allow us to operate on instances of a specific type. Methods use receivers, which are parameters to the method that specify the object it operates on. Method names have the following syntax:

func (t Type) methodName(parameters) returnType

Example:

// 定义一个 Person 类型
type Person struct {
    name string
    age  int
}

// 为 Person 类型定义一个 greet 方法
func (p Person) greet() string {
    return fmt.Sprintf("Hello, my name is %s", p.name)
}

In this example, the greet method is of type Person Association, which accepts a Person instance as the receiver.

Function

A function is an independent block of code independent of any type. They take normal parameters, rather than receivers, and can operate on any type of variable or value. Function names use the following syntax:

func functionName(parameters) returnType

Example:

// 定义一个 add 函数
func add(a, b int) int {
    return a + b
}

Difference

The following table summarizes the differences between methods and functions The main difference between:

##ReceiverYesNoOperation objectType instanceAny type variable/valueSyntax

Features	Method	Function
Association Type	Yes	No
	func (t Type) methodName(parameters) returnType	func functionName(parameters) returnType

Practical case

Example 1: Calculate string length

func main() {
    name := "Go语言"
    fmt.Println("字符串长度：", len(name))
}

Here, the

len function is an independent function, it Accepts a string as argument and returns its length.

Example 2: Translating String

type Text struct {
    content string
}

func (t Text) toUpper() string {
    return strings.ToUpper(t.content)
}

func main() {
    text := Text{content: "Go编程语言"}
    fmt.Println("转译后的字符串：", text.toUpper())
}

In this case,

toUpper is a method that is the same as Text Type association. It receives a Text instance as a receiver and returns a copy translated to uppercase.

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