英文:
Is there a built in function in go for making copies of arbitrary maps?
问题
在Go语言中，没有内置的函数用于复制任意映射（maps）。你可以手动编写一个复制函数，但是我之前在查找类似问题时发现，当我想要进行深度比较映射时，已经有一个内置函数可以实现！所以，类似地，我想知道是否有一个内置的函数、库或包可以在Go语言中进行映射的深度复制。我相信我不是第一个想要复制映射的人。
通过复制，我指的是可以创建两个不同的变量，它们在内容上相同但在内存中引用不同的映射。
英文:
Is there a built in function in go for making copies of arbitrary maps?
I would be able to write one by hand but I found out earlier I was looking a similar question when I wanted to make a deep comparison of maps and there seemed to be a function already built in for that! So similarly, maybe I was wondering if there was an built in or some library or package for making deep copies of maps in golang. I am sure I am not the first person to want to make copies of maps in go.
By copy I mean you can create two different variables that reference a different map in memory even though they are the same content wise.
答案1
得分: 8
更一般的方法是，你可以使用encoding/gob对地图进行编码和解码，将其存储在一个新的变量中。
这种方法的优点是，它甚至可以处理更复杂的数据结构，比如包含地图切片的结构切片。
package main
import (
"bytes"
"encoding/gob"
"fmt"
"log"
)
func main() {
ori := map[string]int{
"key": 3,
"clef": 5,
}
var mod bytes.Buffer
enc := gob.NewEncoder(&mod)
dec := gob.NewDecoder(&mod)
fmt.Println("ori:", ori) // key:3 clef:5
err := enc.Encode(ori)
if err != nil {
log.Fatal("encode error:", err)
}
var cpy map[string]int
err = dec.Decode(&cpy)
if err != nil {
log.Fatal("decode error:", err)
}
fmt.Println("cpy:", cpy) // key:3 clef:5
cpy["key"] = 2
fmt.Println("cpy:", cpy) // key:2 clef:5
fmt.Println("ori:", ori) // key:3 clef:5
}
如果你想了解更多关于gob的信息，可以参考Go博客文章。
英文:
For a more general answer, you can encode your map and decode it in a new variable with encoding/gob.
The advantages of this way is that it'll even work on more complex data structure, like a slice of struct containing a slice of maps.
package main
import (
"bytes"
"encoding/gob"
"fmt"
"log"
)
func main() {
ori := map[string]int{
"key": 3,
"clef": 5,
}
var mod bytes.Buffer
enc := gob.NewEncoder(&mod)
dec := gob.NewDecoder(&mod)
fmt.Println("ori:", ori) // key:3 clef:5
err := enc.Encode(ori)
if err != nil {
log.Fatal("encode error:", err)
}
var cpy map[string]int
err = dec.Decode(&cpy)
if err != nil {
log.Fatal("decode error:", err)
}
fmt.Println("cpy:", cpy) // key:3 clef:5
cpy["key"] = 2
fmt.Println("cpy:", cpy) // key:2 clef:5
fmt.Println("ori:", ori) // key:3 clef:5
}
If you want to know more about gobs, there is a go blog post about it.
答案2
得分: 2
不，没有内置的一行代码来进行深拷贝映射。
英文:
No, there is no built-in one-liner for map deep copy.
However, there is an iterative solution as well as a generic package for deep copy.
答案3
得分: -1
复制一个映射只需要几行简单的代码。只需编写代码，放下每个简单代码都必须在库中的想法，然后享受它！
original := map[string]int{
"Hello": 4,
"World": 123,
}
copy := map[string]int{}
for k, v := range original {
copy[k] = v
}
英文:
Copying a map is a few, trivial lines of code. Just write the code and enjoy letting go of the idea that every simple piece of code has to be in a library!
original := map[string]int{
"Hello": 4,
"World": 123,
}
copy := map[string]int{}
for k, v := range original {
copy[k] = v
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
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