How to clone objects in golang

In Golang, cloning an object can be useful in some situations. For example, when we need to operate on an object and retain its original state. In some cases, we may need to copy one object into another object and want to apply different operations in the new object, while the original object remains unchanged.

In this article, I will introduce how to clone an object in Golang. We'll explore using shallow and deep copies to implement object cloning.

1. Shallow copy

Shallow copy refers to copying an object and only copying the value of the object and references to other objects. In a shallow copy, if a field in the source object points to another object, it will point to the same object in the new object.

The following is a sample code that demonstrates how to use the shallow copy method to implement object cloning:

package main

import "fmt"

type Person struct {
    Name string
    Age  int
    Address *Address
}

type Address struct {
    Street string
    City   string
}

func (p *Person) clone() *Person {
    // Create a new Person struct with the same values as the original
    cloned := *p
    return &cloned
}

func main() {
    original := &Person{
        Name: "John Doe",
        Age:  25,
        Address: &Address{
            Street: "1234 Main St",
            City:   "Anytown",
        },
    }

    // Clone the person
    cloned := original.clone()

    // Update the cloned person's address
    cloned.Address.Street = "5678 Main St"
    cloned.Address.City = "Othertown"

    // Print the original and cloned persons to verify that the original is not affected by the update
    fmt.Println("Original person:", original.Name, original.Age, original.Address.Street, original.Address.City)
    fmt.Println("Cloned person:", cloned.Name, cloned.Age, cloned.Address.Street, cloned.Address.City)
}

In the above code, we define a Person structure, which has Name, Age and Address field. The Address field is a pointer to the Address structure. We define a clone() method for the Person structure, which is used to clone Person objects.

In the main() function, we create a Person object named original, and use the shallow copy method clone() to create a Person object named cloned. We then update the Address field of the cloned object and print out the original and cloned Person objects to verify that the original object is not affected by the update.

2. Deep copy

Deep copy refers to creating a completely independent object that contains all values ​​and references of the source object. Deep copy is used when we need to clone an object but at the same time keep all the values ​​and references of the original object.

The following is a sample code that uses deep copy to implement object cloning:

package main

import (
    "fmt"
    "encoding/json"
)

type Person struct {
    Name string
    Age  int
    Address *Address
}

type Address struct {
    Street string
    City   string
}

func (p *Person) clone() *Person {
    bytes, _ := json.Marshal(p)
    var cloned Person
    json.Unmarshal(bytes, &cloned)
    return &cloned
}

func main() {
    original := &Person{
        Name: "John Doe",
        Age:  25,
        Address: &Address{
            Street: "1234 Main St",
            City:   "Anytown",
        },
    }

    // Clone the person
    cloned := original.clone()

    // Update the cloned person's address
    cloned.Address.Street = "5678 Main St"
    cloned.Address.City = "Othertown"

    // Print the original and cloned persons to verify that the original is not affected by the update
    fmt.Println("Original person:", original.Name, original.Age, original.Address.Street, original.Address.City)
    fmt.Println("Cloned person:", cloned.Name, cloned.Age, cloned.Address.Street, cloned.Address.City)
}

In the above code, we define a Person structure and an Address structure. We define a clone() method for the Person structure, which uses JSON encoding and decoding to perform a deep copy.

In the main() function, we create a Person object named original, and use the deep copy method clone() to create a Person object named cloned. We then update the Address field of the cloned object and print out the original and cloned Person objects to verify that the original object is not affected by the update.

Summary

In Golang, you can use shallow copy and deep copy methods to clone an object. A shallow copy only copies an object's values ​​and references to other objects, while a deep copy copies the entire object, including its references.

Using shallow copies can clone an object faster, but if the values ​​and references of the source object change frequently, the cloned object will also be affected. Using a deep copy preserves all values ​​and references to the original object, but it may require more time and memory to complete. So when using the cloning method, choose the appropriate one based on your needs.

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