Detailed introduction to the method set in Golang

Go language is an emerging programming language. Its elegance, efficiency, and simplicity have attracted the attention of many programmers. The Go language is excellent in many aspects such as syntax, platform support, and performance. It is widely used in data processing, high-concurrency programming, Web programming and other fields, and has extremely high scalability.

The method set in Golang is a part that many developers are not familiar with. This article will introduce the method set in Golang and how to use them.

A method set is a collection of methods that belong to an interface or structure. In the Go language, the method set is divided into a value method set and a pointer method set. The biggest difference is whether the caller can be modified.

The methods in the value method set will not modify the value on which they are called, that is, in the value method set, methods cannot change the state of the value on which they are called. We can use a method set containing a structure type as a receiver, and then the value type can call methods in the value method set.

Take a string as an example. In the Go language, a string is a read-only byte slice, and its value cannot be modified. If we want to modify the string, we must use the pointer method set. The pointer method set method manipulates the value of a variable through a pointer and can change its state. We can use a method set containing a structure pointer type as a receiver, and then the pointer type can call methods in the pointer method set.

In the Go language, if we define a method set, this method set can be applied to all interfaces and structures that have the same methods and implementations. This provides us with an easy way to access shared functionality.

The following is an example of using the value method set and the pointer method set:

package main

import (
    "fmt"
)

type User struct {
    Name string
    Age  int
}

func (u User) GetName() string {
    return u.Name
}

func (u *User) SetName(name string) {
    u.Name = name
}

func main() {
    user := User{
        Name: "Tom",
        Age:  18,
    }
    fmt.Println(user.GetName())
    user.SetName("Jerry")
    fmt.Println(user.GetName())
}

In this example, we define a User structure and define the GetName method in the value method set, This method returns the User's name.

In the pointer method set, we define the SetName method, which can modify the User's name.

The main() function first creates a User instance named "Tom" and prints its name. We then call the SetName method using the pointer to change its name to "Jerry". When the GetName method is called, it returns the new name "Jerry".

In addition to the value method set and pointer method set, we can also use the empty interface as the receiver of the method. Methods implemented using the empty interface can be called on any type of value.

For example, we can define a method that accepts an empty interface as a parameter and prints different types of values:

package main

import (
    "fmt"
)

func PrintValue(v interface{}) {
    fmt.Println(v)
}

func main() {
    PrintValue("Hello, World")
    PrintValue(123)
    PrintValue(3.142)
}

The PrintValue method accepts an empty interface as a parameter and prints its value.

In the main() function, we call the PrintValue method three times, passing different types of values ​​respectively. Regardless of whether strings, integers, or floating point numbers are passed, PrintValue can print out their values.

Summary:

• A method set is a collection of methods, which belong to an interface or structure.
• The method set is divided into a value method set and a pointer method set. The biggest difference is whether the caller can be modified.
• In the Go language, if we define a method set, this method set can be applied to all interfaces and structures that have the same methods and implementations.
• Methods implemented using the empty interface can be called by any type of value.

Although Golang is an emerging programming language, it already has many excellent features, and method set is one of them. Mastering the use of method sets can provide us with convenient and efficient services during the development process.

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