Detailed explanation of golang methods

Go language (Golang), as an emerging high-performance programming language, has received more and more attention and support in the development field in recent years. Among them, the Go method is an important feature of the Go language. It not only provides a more convenient way to organize code, but also allows for better code reuse and maintenance. The following will introduce the concepts, types, definitions and usage of Go methods respectively.

1. The concept of method

In Go language, a method is a function associated with a specific type, which can be called on that type. Methods are usually defined with a receiver parameter, where the receiver parameter represents the type on which the method is called. Through this receiver parameter, the method can access any properties and methods of the type to implement the function of operating on the data.

For example, for a structure type Person, you can define a method SayHello, which returns a string type:

type Person struct {

name string
age  int

}

func (p Person) SayHello() string {

return "Hello, my name is " + p.name + ", I'm " + strconv.Itoa(p.age) + " years old."

}

In the above code, the method SayHello defines a receiver p Person and uses it in the method The receiver's attributes name and age are retrieved, and a string-type greeting is finally returned. After this method is defined, it can be called through an instance of the Person type.

2. Types of methods

Go methods can be divided into two types: value receivers and pointer receivers.

Value type receiver (that is, a copy of the instance value) is usually used in scenarios where the internal state of the instance does not need to be changed. It is defined as:

func (p Person) SayHello() string {

return "Hello, my name is " + p.name + ", I'm " + strconv.Itoa(p.age) + " years old."

}

The pointer type receiver (i.e. the pointer of the instance) is usually used in scenarios where the internal state of the instance needs to be changed. It is defined as:

func (p * Person) IncreaseAge() {

p.age++

}

In the above code, the method IncreaseAge defines a receiver p Person, and modifies the attribute age of the receiver in the method . Note that the pointer type receiver can receive a pointer to the type or a type that requires an address. The method declaration in this form requires "" before the type name. The "*" here is a pointer type. mean.

3. Definition of methods

There are two ways to define Go methods, one is to define the method when the type is declared, and the other is to define a method through a function outside the type.

The method is defined in the type declaration as follows:

type Person struct {

name string
age  int

}

func (p Person) SayHello() string {

return "Hello, my name is " + p.name + ", I'm " + strconv.Itoa(p.age) + " years old."

}

In the above code, the method SayHello is defined within the Person type.

The way to define methods through functions outside the type is as follows:

type Person struct {

name string
age  int

}

func (p Person) SayHello() string {

return "Hello, my name is " + p.name + ", I'm " + strconv.Itoa(p.age) + " years old."

}

func (p *Person) IncreaseAge() {

p.age++

}

In the above code, the method IncreaseAge is defined by the function and added outside of the Person type.

4. Method usage

The method is used similarly to other functions. It can be called in the following two ways:

1. Called through an instance of the type.

p := Person{name: "Tom", age: 18}
p.SayHello() // Hello, my name is Tom, I'm 18 years old.

2. Call through type pointer.

pp := &Person{name: "Jack", age: 20}
pp.IncreaseAge() // Modify the age attribute of pp, at this time pp.age=21.

The above is a detailed introduction to Go methods. For developers who develop using Go, whether through structures or interface types, applying Go methods can better achieve code reuse and maintenance.

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