Python string and array slicing in Swift

SwiftArrayString

import Foundation

extension Array {
    func get (range: Range<Int>) -> Array<T> {
        var subarray = Array<T>()

        for var i = range.startIndex; i < range.endIndex; i++ {
            subarray += [self[i]]
        }

        return subarray
    }

    subscript( range: Range<Int>) -> T[] {
        var subarray = Array<T>()

        let min = range.startIndex
        let max = range.endIndex

        for var i = min; i < max; i++ {
            subarray += [self[i]]
        }

        return subarray
    }

    subscript( tup: (Int, Int) ) -> T[] {
        var (first, last) = tup
            let length = countElements(self)

            if first < 0 {
                first = length + last
            }

            if last < 0 {
                last = length + last
            }

            if first > last {
                first = last
            }

            let r:Range = first...last
            return Array(self).get(r)


    }

}

extension String {
    var length: Int {
        return countElements(self)
    }

    func fromTup( tup: (Int, Int) ) -> String {
        var (first, last) = tup
        let length = countElements(self)

        if first < 0 {
            first = length + last
        }

        if last < 0 {
            last = length + last
        }

        if first > last {
            first = last
        }

        let r:Range = first...last
        return Array(self).get(r).reduce(String(), combine: +)
    }

    subscript( range: Range<Int>) -> String {
        return Array(self).get(range).reduce(String(), combine: +)
    }

    subscript( tup: (Int, Int) ) -> String {

        var (first, last) = tup
        let len = countElements(self)

        if first < 0 {
            first = length + first

            if first < 0 {
                first = 0
            }
        }

        if last < 0 {
            last = length + last

            if last < 0 {
                last = 0
            }
        }

        if first > last {
            first = last
        }

        let r:Range = first...last
        let s = Array(self).get(r).reduce(String(), combine: +)
        return s
    }

}

let s : String = "Apple is a string"
let s2 : String = s[(-6,-1)]
let s3 : String = s[1..6]
let a  = [1,3,5,7,9]
a[(1,2)]