Modify values in copy of slice then append to original slice

Writing a function to copy a slice and modify the values on the items in the copy of the slice then append the copy to the original. It appears the code is not only modifying the copy of the slice but also the original slice.

Go Playground

import "fmt"

type Item struct {
	name   string
	number int
}

func main() {
	names := []string{"a", "b"}
	numbers := []int{1, 2}

	items := []*Item{}

	for _, name := range names {
		item := &Item{name: name}
		items = append(items, item)
	}

	for n, i := range numbers {
		if n > 0 {
			fmt.Println(n, "make a copy of the items")
			itemCopies := make([]*Item, len(items))
			copy(itemCopies, items)

			fmt.Println(n, "set the numbers on the copies")
			for _, item := range itemCopies {
				item.number = i
			}

			fmt.Println(n, "append the copies to the original")
			items = append(items, itemCopies...)
		} else {

			fmt.Println(n, "first pass set all the items to the first number")
			for _, item := range items {
				item.number = i
			}
		}
	}

	for n, i := range items {
		fmt.Printf("%d %+v\n", n, *i)
	}
}

What I'm actually seeing

0 {name:a number:2}
1 {name:b number:2}
2 {name:a number:2}
3 {name:b number:2}

What I expected to see

0 {name:a number:1}
1 {name:b number:1}
2 {name:a number:2}
3 {name:b number:2}

@JimB was right you copy pointers,

I suggest define a copy function belong Struct Item to new a duplicate

package main
import "fmt"
type Item struct {
name   string
number int
}
func (it *Item) copy() *Item {
return &Item{
name:   it.name,
number: it.number,
}
}
func main() {
names := []string{"a", "b"}
numbers := []int{1, 2}
items := []*Item{}
for _, name := range names {
item := &Item{name: name}
items = append(items, item)
}
for n, i := range numbers {
if n > 0 {
fmt.Println(n, "make a copy of the items")
itemCopies := make([]*Item, len(items))
for j := 0; j < len(items); j++ {
itemCopies[j] = items[j].copy()
}
fmt.Println(n, "set the numbers on the copies")
for _, item := range itemCopies {
item.number = i
}
fmt.Println(n, "append the copies to the original")
items = append(items, itemCopies...)
} else {
fmt.Println(n, "first pass set all the items to the first number")
for _, item := range items {
item.number = i
}
}
}
for n, i := range items {
fmt.Printf("%d %+v\n", n, *i)
}
}