golang structure method

Golang is a modern programming language that is not only simple and easy to use, but also very efficient when writing and maintaining large code bases. Golang supports object-oriented programming, and one of the concepts included is structures. Let’s take a look at the related knowledge of structures and methods in Golang.

1. What is a structure?

In Golang, a structure is a custom data type composed of a set of fields of the same type or different types. You can think of a structure as a template that describes an object's set of properties and methods. The following is a simple structure example:

type Person struct {
    Name string
    Age  int
}

In this example, we define a structure named Person, which contains two fields Name and Age, representing the person's name and age respectively. The fields of a structure can have different data types, including any built-in type or custom type. For example, if we want to add a work experience field, we can do this:

type Person struct {
    Name string
    Age  int
    Experience []string
}

2. What is the method?

Methods are functions associated with the structure. They can perform operations on the structure and access and modify its fields. In Golang, method definition is very similar to function definition, but methods need to add a receiver type before the function name. The receiver type can be a structure or any other type.

The following is a simple method example:

type Person struct {
    Name string
    Age  int
}

func (p Person) SayHello() {
    fmt.Println("Hello, my name is", p.Name)
}

In this example, we define a method SayHello, which has a Person object named p as the receiver. Since we have the Person object as the receiver, within the method we can access its fields and perform any other operations. For example, we can call this method using the following code:

person := Person{Name: "Alice", Age: 25}
person.SayHello()

This will output "Hello, my name is Alice" to the console.

3. The difference between structure methods and functions

In Golang, functions and methods are two different concepts, although their syntax is very similar. Here are some differences between structure methods and functions:

1. Methods are functions associated with a structure, while functions are independent entities. Therefore, methods can only be called through structure objects, while functions can be called directly.
2. Methods can access and modify the fields of a structure, while functions cannot access or modify the fields of a structure unless they pass a structure object as a parameter.

4. Pointer methods and value methods of structures

Like functions, methods can also be defined on structure pointers, which are called pointer methods. These methods receive a pointer to a structure and can modify the fields of the structure. Here is an example of a pointer method:

type Person struct {
    Name string
    Age  int
}

func (p *Person) UpdateName(name string) {
    p.Name = name
}

In this example, we define a method UpdateName which has a named pointer to a Person object as the receiver. Since we are using pointers as receivers, we can modify the fields of the structure inside the method. For example, use the following code to call this method to update p's name to "Bob":

person := &Person{Name: "Alice", Age: 25}
person.UpdateName("Bob")

In the above example, we pass a pointer to the Person object to the method, which will modify the name of the object. .

Value methods (without pointers) can only be executed on a copy of the structure and therefore cannot modify the original structure. In most cases we should use pointer methods so that we can modify the structure.

5. Summary

Like functions, methods are another basic concept of Golang. Used in conjunction with structs, they are a very useful tool for writing more structured code. In this article, we introduce the relevant knowledge of structures and methods in Golang, including the definition of structures, the definition of methods, and the differences between pointer methods and value methods. I hope this article will help you understand Golang's object-oriented programming.

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