如何从Golang中的切片获取结构指针

Question

Here is the code:

package main

import (
    "fmt"
)

type demo struct {
     name string
}

func main() {
     demo_slice := make([]demo, 3)
     demo_slice[0] = demo{"str1"}
     demo_slice[1] = demo{"str2"}
     demo_slice[2] = demo{"str3"}

     point_demo_slice := make([]*demo, 3)
     for index, value := range demo_slice {
          fmt.Printf("\n%v==++++++++++++++%p\n", value, &value)
          point_demo_slice[index] = &value
     }
}

The result:

{str1}==++++++++++++++0x20818a220

{str2}==++++++++++++++0x20818a220

{str3}==++++++++++++++0x20818a220

0x20818a220 is the last element's pointer value.

Why are all the pointer values ​​the same?

How can I get those right pointer values?

Answer 1

You're not referring to the elements of the slice but the local value variable:

fmt.Printf("\n%v==++++++++++++++%p\n", value, &value)

Hence all the pointer values will be the same (the address of local variable value ). If you want pointers to the elements of the slice, then take the address of the appropriate element:

fmt.Printf("\n%v==++++++++++++++%p\n", demo_slice[index], &demo_slice[index])

This will produce the following output, all pointers are different:

{str1}==++++++++++++++0x104342e0

{str2}==++++++++++++++0x104342e8

{str3}==++++++++++++++0x104342f0