Let’s talk about the definition and use of methods in Golang

Golang language is a very popular programming language in recent years. Its simplicity, efficiency and high readability are deeply loved by programmers. In Golang, defining methods is a very important part. For writing efficient programs, the definition of methods must be correct, concise, and easy to understand.

1. Definition of methods

Methods in Golang are implemented by functions, but their syntax has some differences. In Golang, a method is defined as a function with a special receiver parameter. The receiver can be of any type, but must be declared before the function name. The following is an example of a method definition:

package main

import "fmt"

type MyInt int

func (i MyInt) Print() {
    fmt.Println(i)
}

func main() {
    var i MyInt = 100
    i.Print()
}

In the above code, we define a MyInt type and a print method. This method outputs the receiver i, instantiates a MyInt type in the main function, and outputs it through the i.Print() method.

2. Association between types and methods

In Golang, the association between methods and types is achieved through receivers. In the above code, we use the MyInt type as the method receiver, which associates the method with the MyInt type. Note that the receiver must be declared using a type name rather than an alias. For example:

type MyInt int

If we change MyInt to i, the definition of the receiver will be wrong:

type i int        // 错误的示例

func (i MyInt) Print() {
    fmt.Println(i)
}

3. Pointer Receiver

In In Golang, in addition to value receivers, pointer receivers can also be used to define methods. A pointer receiver can modify what the receiver points to, thereby changing its value. The following is an example of defining a method using a pointer receiver:

package main

import "fmt"

type MyInt int

func (i *MyInt) Add(n MyInt) {
    *i += n
}

func main() {
    var i MyInt = 100
    i.Add(50)
    fmt.Println(i)
}

In the above code, we define an Add method that uses a pointer receiver to modify the value of the MyInt type. In the main function, we instantiate a MyInt type and add 50 to its value. Since we used a pointer receiver, the value can be modified inside the method, and the output result is 150.

4. Which one is better, value receiver or pointer receiver?

In practical applications, we should choose a value receiver or a pointer receiver according to the actual situation. Pointer receivers should be used when we need to modify the value of the receiver. When we only need to read the value of the receiver and do not need to modify it, we should use the value receiver. Value receivers are generally used when the receiver object does not need to be modified, while pointer receivers are used when the receiver object needs to be modified.

Summary:

Through the above explanation, I believe everyone has understood the definition and use of methods in Golang. As an important feature of Golang, the correct use of methods can bring many benefits such as efficiency, simplicity and ease of maintenance to the program.

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