Split String into groups with specific length

Question

How can I split the given String in Swift into groups with given length, reading from right to left?

For example, I have string 123456789 a

Answer 1

Swift 4

I think the extension method is more useful.

extension String{

    public func splitedBy(length: Int) -> [String] {

        var result = [String]()

        for i in stride(from: 0, to: self.characters.count, by: length) {
            let endIndex = self.index(self.endIndex, offsetBy: -i)
            let startIndex = self.index(endIndex, offsetBy: -length, limitedBy: self.startIndex) ?? self.startIndex
            result.append(String(self[startIndex..

the example of use:

Swift.debugPrint("123456789".splitedBy(length: 4))
// Returned ["1", "2345", "6789"]