如何在GO编程中的特定索引处更改byte []中的某些字节？

Question

I have a []byte that which is essentially a string, in this array I have found something I want to change using index:

content []byte
key []byte
newKey []byte
i = bytes.Index(content, key)

So I have found key in content (at index I), now I want to replace key with newKey but I can't seem to find a way to add it in I was trying the obvious thing that wouldn't work :)

content[i] = newKey

Is there some function that allows me to replace "key" with "newKey" within content []byte?

Thanks,

Answer 1

Following the article "Go Slices: usage and internals", you can use copy in order to create a slice with the right content:

playground

package main

import "fmt"

func main() {
    slice := make([]byte, 10)
    copy(slice[2:], "a")
    copy(slice[3:], "b")
    fmt.Printf("%v
", slice)
}

Output:

[0 0 97 98 0 0 0 0 0 0]

---

In your case, if len(key) == len(newJey):

playground

package main

import "fmt"
import "bytes"

func main() {
    content := make([]byte, 10)
    copy(content[2:], "abcd")
    key := []byte("bc")
    newKey := []byte("xy")
    fmt.Printf("%v %v
", content, key)

    i := bytes.Index(content, key)
    copy(content[i:], newKey)
    fmt.Printf("%v %v
", content, newKey)
}

Output:

[0 0 97 98 99 100 0 0 0 0] [98 99]
[0 0 97 120 121 100 0 0 0 0] [120 121]