package main
import "fmt"
func main() {
a := [...]int{0, 1, 2, 3}
x := a[:1]
y := a[2:]
x = append(x, y...)
x = append(x, y...)
fmt.Println(a, x)
}
Choices:
Answer: [0 2 3 3] [0 2 3 3 3]
Run it on Go play.
Key points:
y is [2 3],
and the slice x is [0] with three free element slots (in other words, its capacity is 4),
append call changes the slice x to [0 2 3] with one free element slot.
And as the slice x and the array a share elements (before line 10),
the array a is changed to [0 2 3 3].
The slice y and the array a also share elements,
so the slice y is changed to [3 3].
x has not enough free capacity,
the 2nd append call allocates a new backing array for the slice x.
So the call doesn't modify the array a.
The slice x is changed to [0 2 3 3 3].
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