before golang method

Why do you need to learn golang methods?

As the times progress, computer software development has become a part of productivity. The emergence of Go language (golang) has brought a new choice to software development. When developing applications using golang, methods are an important part of writing code. Specifically, some rules need to be followed before golang methods to achieve efficient and reusable code. This article will comprehensively introduce the relevant content before golang methods. The purpose is to help readers better master golang programming skills and improve development efficiency.

Before the golang method: Understand the basic knowledge

Golang is an object-oriented (OOP) language, so the method is one of the very important methods. If you have ever used other programming languages, you will find that Golang's methods are neat, clear, readable and easy to use.

For students who have not yet understood the golang method, let’s first understand a few basic concepts.

What is the method?

A method is a function belonging to a specific type, which can be called through an instance of this type. Syntactically, a method includes a receiver (Receiver) and a function body. The receiver is a variable of a specific type.

You can use a structure (Struct) to define this type, and then define methods on the structure. For example:

type Circle struct {
    radius float64
}

func (c Circle) Area() float64 {
    return math.Pi * c.radius * c.radius
}

In this example, the receiver c Circle is a structure type, which has a property radius of type float64 . Area is a method that returns the area of ​​a circle. Since Area is defined on the Circle structure, it becomes a method of the structure Circle.

What is the difference between functions and methods?

Functions and methods are two different concepts, but you might think that they are very similar.

A function is an independent piece of code that can be called anywhere.

Methods provide a way to operate on a specific type, so they are usually object-related.

The difference between functions and methods is mainly reflected in their names. Functions have an operation name, while methods have an operation name and a receiver type.

The syntax before golang method

We have already understood what a method is before, so how to define a method in golang? Its definition syntax is as follows:

func (接收器变量 接收器类型) 方法名(参数列表) (返回参数) {
    // 函数体
}

Receiver variable: the parameter name in the receiver. For ease of use, it is recommended not to use variable names with the first letter capitalized.

Receiver type: Specify the parameter type of the receiver.

Method name: Custom method name. The method name can be any legal identifier.

Parameter list: The parameter list of the method. The parameter list can be empty.

Return parameters: return parameters of the method. The return parameter can be empty.

When the method is called, the receiver will automatically become the first parameter of the method. Therefore, other fields or methods in the receiver can be used directly in the method. The receiver can be a value type or a reference type. If the receiver is a value type, it means it is a copy of that type. If the receiver is a reference type, it means it is an instance of that type.

Sample code:

type rect struct {
    width, height int
}

func (r rect) area() int {
    return r.width * r.height
}

func (r rect) perimeter() int {
    return 2*r.width + 2*r.height
}

func main() {
    r := rect{width: 10, height: 5}
    fmt.Println("area: ", r.area())
    fmt.Println("perimeter: ", r.perimeter())

    rp := &r
    fmt.Println("area: ", rp.area())
    fmt.Println("perimeter: ", rp.perimeter())
}

This code example defines a data type named rect with two fields: width and height . Two methods are also defined: area method and perimeter method. The area method returns the area, and the perimeter method returns the perimeter.

In the main function, we first create an instance r of rect. We then used instance r to call the area and perimeter methods respectively and output their values. Finally, we use a pointer rp pointing to r, also call the area and perimeter methods, and output their values.

Use before golang method

In golang, you can add * after the receiver to use a pointer type receiver. At this point, inside the method, we can easily modify the other fields that the receiver points to. This is useful for modifying data without directly returning the modified results.

Sample code:

type Person struct {
    name string
}

func (p *Person) updateName(newName string) {
    p.name = newName
}

func main() {
    person := Person{name: "John"}

    fmt.Println("Before update: ", person.name)

    person.updateName("Smith")

    fmt.Println("After update: ", person.name)
}

This code example defines a data type named Person and defines a method updateName. In the main function, we create an instance of a variable called person and print out its initial value. The updateName method is then called, which changes the person's name to "Smith". Finally, we output the person's name again and verify its change. Since the updateName method accesses person through a pointer, it will directly modify the name field of person.

Summary

Using methods in golang is a very important skill. They are the key to making your code cleaner, more specific, and better maintainable. Since golang method execution is very efficient, they can also significantly improve your application performance.

After mastering the basic concepts, we need to continue to practice and consolidate them in practice. By writing actual Golang code and introducing methods, you can better understand the core concepts and operational skills before Golang methods, and perform better development and maintenance in actual applications.

The above is the detailed content of before golang method. For more information, please follow other related articles on the PHP Chinese website!