Swift - Leave last X number items in array

Question

I have array with 50 items. How to leave in the array only the last 30 items without for loop?

Answer 1

You can use an ArraySlice :

let lastThirty = array[20...]

Note that lastThirty is of type ArraySlice , so to get it back as an array, you can do:

let lastThirtyArray = Array(lastThirty)

You can read more about ArraySlice s here .

Answer 2

  let a1 = [1,2,3,4,5]
  print(a1[2...])

so you just need the array[20...]

or array.dropfirst(20)

Answer 3

What you are looking for is collections method suffix

func suffix(_ maxLength: Int) -> ArraySlice

It will return n elements up to the number of elements in your collection:

let input = Array(1...100)
let last30 = input.suffix(30)  // [71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]