Given a hexadecimal string in Swift, convert to hex value

Question

Suppose I am given a string like this:

D7C17A4F

How do I convert each individual character to a hex value?

So D

Answer 1

My variation of @martin-r answer:

extension String {

    func hexToByteArray() -> [UInt8] {
        let byteCount = self.utf8.count / 2
        var array = [UInt8](count: byteCount, repeatedValue: 0)
        var from = self.startIndex
        for i in 0..