The concept and usage of method receiver in golang

Go language is an open source programming language that is designed to be a very efficient programming method. Compared with other programming languages, the Go language has many unique features, one of which is the method receiver (Method Receiver). This article will mainly introduce the concept and usage of method receivers in Go language.

1. What is a method receiver?

In the Go language, method receivers are special functions that are used to bind to a specific type and allow values ​​on that type to call methods. Method receivers are also called receiver functions or simply receivers. Receivers surround type definitions, which allow developers to define methods on types. The method receiver specifies the parameters of the method, as well as the type of the parameters.

2. Syntax of method receiver

The receiver of a method is a parameter (or a group of parameters) specified before the function name. Given below is the complete format of a method with a receiver of type T:

func (t T) methodName(parameter_list)(return_type_list){
    //Code Block
}

where the receiver is specified before the function name and has one parameter of type T. You can use a value of pointer type T as a receiver. If methodName is a method that points to a pointer of type T, you can use a value of type T or *T as its receiver.

About the receiver, several concepts you need to know are as follows.

• T: Type, that is, the parameter type of the method receiver.
• methodName: Method name.
• parameter_list: Parameter list, the same as function parameter list.
• return_type_list: Return value list, the same as function return value list.

For example, in Go language, you can define a Person type like this, and then define a GetAge() whose receiver is Person type Method:

// Person with name and age as attributes.
type Person struct {
    name string
    age  int
}

// Method to get person's age
func (p Person) GetAge() int {
    return p.age
}

func main() {
    // Create a person object
    person := Person{"Alice", 25}

    // Calling GetAge() Method.
    fmt.Println("Age of the person is:", person.GetAge()) // Output: Age of the person is: 25
}

In the above example, we defined a type Person and passed it as a receiver to a GetAge() method. Use the GetAge() method to get the age of an object of type Person.

3. Using pointer types as receivers

You can use the value of pointer type T as a receiver. If methodName is a method that points to a pointer of type T (that is, T), you can use a value of type T or T as its receiver. For example, in Go language, you can define a Person type like this, and define a SetName() method whose receiver is a Person type pointer:

// Person with name and age as attributes.
type Person struct {
    name string
    age  int
}

// Method to set person's name
func (p *Person) SetName(name string) {
    p.name = name
}

func main() {
    // Create person object
    person := &Person{"Alice", 25}

    // Calling SetName() method
    person.SetName("Bob")

    // Retrieved person's name
    fmt.Println("The person's name is:", person.name) // Output: The person's name is: Bob
}

In the above example, we define a type Person and pass it as a receiver of pointer type *Person to the method SetName( ). Use the SetName() method to set the name of the Person type object.

4. Summary

In the Go language, a method receiver is a special function that is used to bind to a specific type and allows value to call the method. When defining a receiver method, you need to specify a receiver type before the function name. The syntax is as follows:

func (t T) methodName(parameter_list)(return_type_list){
    //Code Block
}

Where, T is the receiver type, which can be any type. Method receivers include type definitions, method names, parameters, and return types. When using the pointer type T as a receiver, you can use a value of type T or *T as its receiver. Defining and using method receivers in Go language can improve the readability and reusability of programs.

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