In Swift, what's the cleanest way to get the last two items in an Array?

Question

Is there a cleaner way to get the last two items of an array in Swift? In general, I try to avoid this approach since it's so easy to be off-by-one with the indexes. (Using Swift 1.2 for this example.)

// Swift -- slices are kind of a hassle? let oneArray = ["uno"] let twoArray = ["uno", "dos"] let threeArray = ["uno", "dos", "tres"]  func getLastTwo(array: [String]) -> [String] {     if array.count <= 1 {         return array     } else {         let slice: ArraySlice<String> = array[array.endIndex-2..<array.endIndex]         var lastTwo: Array<String> = Array(slice)         return lastTwo     } }  getLastTwo(oneArray)   // ["uno"] getLastTwo(twoArray)   // ["uno", "dos"] getLastTwo(threeArray) // ["dos", "tres"] 

I was hoping for something closer to Python's convenience.

## Python -- very convenient slices myList = ["uno", "dos", "tres"] print myList[-2:] # ["dos", "tres"] 

Answer 1

With Swift 5, according to your needs, you may choose one of the following patterns in order to get a new array from the last two elements of an array.

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#1. Using Array's suffix(_:)

With Swift, objects that conform to Collection protocol have a suffix(_:) method. Array's suffix(_:) has the following declaration:

func suffix(_ maxLength: Int) -> ArraySlice<Element> 

Returns a subsequence, up to the given maximum length, containing the final elements of the collection.

Usage:

let array = [1, 2, 3, 4] let arraySlice = array.suffix(2) let newArray = Array(arraySlice) print(newArray) // prints: [3, 4] 

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#2. Using Array's subscript(_:)

As an alternative to suffix(_:) method, you may use Array's subscript(_:) subscript:

let array = [1, 2, 3, 4] let range = array.index(array.endIndex, offsetBy: -2) ..< array.endIndex //let range = array.index(array.endIndex, offsetBy: -2)... // also works let arraySlice = array[range] let newArray = Array(arraySlice) print(newArray) // prints: [3, 4]