How to copy end of the Array in swift?

Question

There must be some really elegant way of copying end of the Array using Swift starting from some index, but I just could not find it, so I ended with this:

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Answer 1

This is one possible solution, there are probably a few more

let array = [1, 2, 3, 4, 5]
let endOfArray = Array(array[2..<array.endIndex]) // [3, 4, 5]

Or with dynamic index and range check

let array = [1, 2, 3, 4, 5]
let index = 2
let endOfArray : [Int]
if index < array.count {
  endOfArray = Array(array[index..<array.endIndex]) // [3, 4, 5]
} else {
  endOfArray = array
}

The re-initializition of the array is needed since the range subscription of Array returns ArraySlice<Element>

Answer 2

You could use filter

func getEndOfArray( arr : [Int], fromIndex : Int? = 0) -> [Int] {
    let filteredArray = arr.filter({$0 <= fromIndex})

    return filteredArray
}

took the liberty of changing to [Int] for the sake of this example.

Answer 3

You can use suffix:

let array = [1,2,3,4,5,6]
let lastTwo = array.suffix(2) // [5, 6]

As mentioned in the comment: This gives you an ArraySlice object which is sufficient for most cases. If you really need an Array object you have to cast it:

let lastTwoArray = Array(lastTwo)

Answer 4

You can subscript an open ended range now. This will include elements starting at index 5.

Swift 4.2

array[5...]

Answer 5

You could use the new method removeFirst(_:) in Swift 4

var array = [1, 2, 3, 4, 5]
array.removeFirst(2)
print(array) // [3, 4, 5]

Answer 6

And another one ...

let array = [1, 2, 3, 4, 5]
let fromIndex = 2
let endOfArray = array.dropFirst(fromIndex)
print(endOfArray) // [3, 4, 5]

This gives an ArraySlice which should be good enough for most purposes. If you need a real Array, use

let endOfArray = Array(array.dropFirst(fromIndex))

An empty array/slice is created if the start index is larger than (or equal to) the element count.