A brief analysis of the declaration and usage of methods in golang

Golang is an open source programming language developed by Google and released in 2009. It has the characteristics of simplicity, clarity, efficiency, and parallelism, and is widely used to build high-performance Web applications, network services, etc. Among them, method is one of the important concepts that supports object-oriented programming in Golang.

Methods in Golang are functions that act on the receiver. They can be thought of as functions of a certain type, used to operate on objects of that type. Let's introduce Golang's method declaration and its use.

The Golang method declaration format is as follows:

func (receiver_name ReceiverType) MethodName(parameter_list) (return_type_list) {
    // method body
}

Among them, receiver_name is the name of the receiver, ReceiverType is the type of the receiver, parameter_list is the parameter list, and return_type_list is the return value list. The format of the method name, parameter list, and return value list is the same as that of an ordinary function.

In Golang, there are two ways to set receivers: value receivers and pointer receivers.

The declaration format of the value receiver is:

func (v ValueTypeName) MethodName(parameter_list) (return_type_list) {
    // method body
}

The declaration format of the pointer receiver is:

func (v *ValueTypeName) MethodName(parameter_list) (return_type_list) {
    // method body
}

Among them, ValueTypeName is the type name of the receiver. Value receivers and pointer receivers have different characteristics when used. Modifications of the receiving object by the value receiver will not affect the original object, while the pointer receiver can modify the value of the original object.

The example is as follows:

type Person struct {
    name string
    age  int
}

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

func (p *Person) setAge(newAge int) {
    p.age = newAge
}

func main() {
    p1 := Person{"John", 25}
    p1.sayHello() // Hello, my name is John

    p1.setAge(30)
    fmt.Println(p1.age) // 输出：30
}

In this example, two methods are defined in the Person structure: sayHello and setAge. sayHello uses a value receiver, which simply prints out its name; setAge uses a pointer receiver, which can modify the age attribute of the receiver.

The selection of value receivers and pointer receivers requires attention to some details. One of the main differences is that when the value of the receiver needs to be modified, a pointer receiver must be used. Otherwise, once the method is executed, the receiver The value of the controller will be discarded and the original value will not be affected.

In general, Golang's method is a very convenient and flexible object-oriented programming method. We can use methods to manipulate types and implement convenient functionality. Whether to use a value receiver or a pointer receiver needs to be chosen based on specific needs. I believe that if you master the use of methods, you can better take advantage of Golang.

The above is the detailed content of A brief analysis of the declaration and usage of methods in golang. For more information, please follow other related articles on the PHP Chinese website!