[Go] 슬라이스의 얕은 복사와 깊은 복사 (Shallow Copy and Deep Copy of Slices)

개요

슬라이스의 얕은 복사와 깊은 복사에 대해서

 

 

1. 얕은 복사

package main

import (
	"fmt"
	"sort"
)

type obj struct {
	Name string
	Age  int32
}

func main() {

	list1 := []*obj{
		{Name: "A", Age: 1},
		{Name: "B", Age: 2},
		{Name: "C", Age: 3},
	}
	list2 := list1

	sort.Slice(list2, func(i, j int) bool {
		return list2[i].Age < list2[j].Age
	})

	fmt.Printf("List1 [%p]\n", list1)
	for _, item := range list1 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}

	fmt.Printf("List2 [%p]\n", list2)
	for _, item := range list2 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}
}

결과값:

List1 [0xc0000a8060]
Name: A, Age: 1 [0xc0000a8078]
Name: B, Age: 2 [0xc0000a8090]
Name: C, Age: 3 [0xc0000a80a8]
List2 [0xc0000a8060]
Name: A, Age: 1 [0xc0000a8078]
Name: B, Age: 2 [0xc0000a8090]
Name: C, Age: 3 [0xc0000a80a8]

슬라이스가 같은 주소값(0xc0000a8060)을 가지며 원본도 같이 정렬 된 것을 확인

 

 

2. 깊은 복사 (copy)

package main

import (
	"fmt"
	"sort"
)

type obj struct {
	Name string
	Age  int32
}

func main() {

	list1 := []*obj{
		{Name: "C", Age: 3},
		{Name: "B", Age: 2},
		{Name: "A", Age: 1},
	}

	list2 := make([]*obj, len(list1))

	copy(list2, list1)

	sort.Slice(list2, func(i, j int) bool {
		return list2[i].Age < list2[j].Age
	})

	fmt.Printf("List1 [%p]\n", list1)
	for _, item := range list1 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}

	fmt.Printf("List2 [%p]\n", list2)
	for _, item := range list2 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}
}

결과값:

List1 [0xc00009c060]
Name: C, Age: 3 [0xc00009c078]
Name: B, Age: 2 [0xc00009c090]
Name: A, Age: 1 [0xc00009c0a8]
List2 [0xc00009c0c0]
Name: A, Age: 1 [0xc00009c0a8]
Name: B, Age: 2 [0xc00009c090]
Name: C, Age: 3 [0xc00009c078]

원본 슬라이스(0xc00009c060)와 다른 주소값(0xc00009c0c0)을 가진 것을 확인

 

https://pkg.go.dev/builtin#copy

builtin package - builtin - Go Packages

 

 

3. 깊은 복사 (append)

package main

import (
	"fmt"
	"sort"
)

type obj struct {
	Name string
	Age  int32
}

func main() {

	list1 := []*obj{
		{Name: "C", Age: 3},
		{Name: "B", Age: 2},
		{Name: "A", Age: 1},
	}

	var list2 []*obj
	list2 = append(list2, list1...)

	sort.Slice(list2, func(i, j int) bool {
		return list2[i].Age < list2[j].Age
	})

	fmt.Printf("List1 [%p]\n", list1)
	for _, item := range list1 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}

	fmt.Printf("List2 [%p]\n", list2)
	for _, item := range list2 {
		fmt.Printf("Name: %s, Age: %d [%p]\n", item.Name, item.Age, item)
	}
}

결과값:

List1 [0xc000116060]
Name: C, Age: 3 [0xc000116078]
Name: B, Age: 2 [0xc000116090]
Name: A, Age: 1 [0xc0001160a8]
List2 [0xc0001160c0]
Name: A, Age: 1 [0xc0001160a8]
Name: B, Age: 2 [0xc000116090]
Name: C, Age: 3 [0xc000116078]

원본 슬라이스(0xc000116060)와 다른 주소값(0xc0001160c0)을 가진 것을 확인

 

 

https://pkg.go.dev/builtin#append

builtin package - builtin - Go Packages