let numbers = [ 2, 3, 5, 7, 11 ]

let first2 = numbers.prefix(2)
//first2 is [ 2, 3 ] ArraySlice<Int>

let last3 = Array(numbers.suffix(3))
//last3 is [ 5, 7, 11 ] Array<Int>

let first3 = numbers[...2]
//first3 is [ 2, 3, 5 ]

let last4 = numbers[(numbers.count-4)...]
//last4 is [ 3, 5, 7, 11 ]

print(first2, type(of: first2))
print(last3, type(of: last3))
print(first3, type(of: first3))
print(last4, type(of: last4))