Swift Extension for Array

arrayLastObjects

extension Array {
    // Underscore is to opt out of Swift forcing an external name for
    // the default property.
    func lastObjects(_ c:Int = 1) -> Array? {
        if (c == 0) {
            return Array()
        }
        else if (c < 0) {
            return nil
        }
        var length = self.count
        var lastIndex = length - 1
        var startIndex = length - c
        return Array(self[startIndex...lastIndex])
    }
}