arrays - Go slices - capacity/length?

Question

Trying to learn Go from the tutorial right now, and have a pretty basic question:

 func main() {
  a := make([]int, 5)
  // [0,0,0,0,0] len=5 cap=5

  b := make([]int, 0, 5)
  // [] len=0 cap=5

  c := b[:2]
  // [0,0] len=2 cap=5

  d := c[2:5]
  // [0,0,0] len=3 cap=3
}

Why does c look like [0,0] and have length 2? b was not originally zero'ed hence it being []. So does setting c to b[:2] zero out the first two elements?

Also, why is the capacity of d 3? Very confused.

Thanks in advance.

Answer 1

Waitting for answers