package main import "fmt" func subis(is []int) []int { return append(is, 5) } func main() { is := []int{1, 2, 3, 4} subis(is[2:3]) fmt.Println(is) }

In this code, the following happens:

is := []int{1, 2, 3, 4}
subis(is[2:3])
fmt.Println(is)

is[2:3] is a slice containing a single element: 3.

The function subis takes a slice is []int and returns a new slice obtained by adding the number 5 to the original slice using append.

However, in main, the result of calling subis is not assigned back, so the original slice is remains unchanged.

The output will be:

[1 2 3 4]

If we had assigned the result, for example:

is = subis(is[2:3])

then is would become the slice [3 5].

Thus, in the current code, is does not change because the result of append is not saved.