The slice() method belongs to the concrete value members of the class AbstractIterator. It is defined in the class Iterator. It creates a new iterator for the interval given in the slice. The first value present in the slice indicates the start of the element in the new iterator and the second value present in the slice indicates the end.
def slice(from: Int, until: Int): Iterator[A]
Where, from implies index of the first element and until implies index of the first element following the slice.
It returns a new iterator with elements from from until until.
2 3 4
Here, if the interval present in the slice is like (n, m) then the elements will be printed from the nth index till (m-1)th index. The functions hasNext and next are used here to print the elements of the new iterator.
2 4 5
Here, the elements are printed from the index zero till the second index.