golang structure modification

Golang is a statically compiled language, and its structure is a very useful data type. In Golang, structures can be used to describe the properties and methods of an entity, can store different types of data, and can also be nested with other structures to create complex data structures. However, when we use structure types in Golang, we sometimes need to modify them. This article will introduce how to modify structures in Golang.

1. Definition of structure

In Golang, a structure can be defined with a set of fields. You can use the following code to define a structure containing two fields (one of type int and one of type string):

type Person struct {
    Age  int
    Name string
}

In this example, we define a structure called Person, which has Two fields: Age and Name. Note that structure field names must start with a capital letter. This is so that they can be exported for use in other packages.

2. Initialization of the structure

In Golang, you can use the following code to initialize the structure:

p := Person{Age: 18, Name: "John"}

This creates a Person object named p , its Age attribute is 18, and its Name attribute is "John".

3. Access to the structure

In Golang, you can use the following code to access the fields in the structure:

fmt.Println(p.Age)
p.Age = 20

The above code will output the Age attribute of p , and modify it to 20.

4. Definition of structure methods

In addition to defining structures, we can also define methods on structures. A method is a function that can access the fields of a structure and can read and modify the values ​​of the structure. You can define a structure method using the following code:

func (p *Person) SetAge(age int) {
    p.Age = age
}

In this example, we define a structure method called SetAge. It accepts a parameter of type int and assigns it to the Age field of the structure.

5. Modification of the structure

In Golang, you can use the dot operator to access the fields of the structure, or you can modify the values ​​of the fields of the structure through pointers. For example, the following code will output the Age property of p and modify it to 20.

fmt.Println(p.Age)
p.Age = 20

If you want to modify the value of the structure inside the function, you must use a pointer. For example:

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

SetName(&p, "Jim")

In this example, we pass the pointer of the Person object to the SetName function. The function parameter p is a pointer to the Person object, which can be modified to "Jim" through the pointer.

6. Nesting of structures

Structures can be nested in other structures. Doing so allows you to create more complex data structures. For example:

type Address struct {
    City  string
    State string
}

type Family struct {
    Address Address
    Members []Person
}

In this example, we define a Family structure, where Address is a nested structure type that contains two fields: City and State. The Family structure also contains a slice containing multiple Person types.

7. Modification of structures

When modifying nested structures, you need to access them like fields, such as the Address structure in the Family structure:

func SetCity(f *Family, city string) {
    f.Address.City = city
}

SetCity(&f, "New York")

In this example, we define a SetCity method on the Family structure, which accepts a pointer to the Family object and sets its Address.City field to "New York".

8. Clone of structure

Sometimes we need to clone a structure object. In this case, we can use the following method:

func Clone(p Person) Person {
    return p
}

c := Clone(p)

In this example, We defined a function named Clone, which accepts a Person object and returns a new Person object, thus successfully creating a copy of the structure object.

9. Summary

In Golang, structures can be used to easily store and operate complex data types. When you need to modify the value of the structure, you can use pointers to access and modify it. Structures can nest other structures to create more complex data structures. By cloning a struct, you can create a new struct object, which is more convenient.

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