How to convert Data to hex string in swift

Question

I want the hexadecimal representation of a Data value in Swift.

Eventually I\'d want to use it like this:

let data = Data(base64Encoded: \"aGVsbG8gd2         


        

Answer 1

This doesn't really answer the OP's question since it works on a Swift byte array, not a Data object. And it's much bigger than the other answers. But it should be more efficient since it avoids using String(format: ).

Anyway, in the hopes someone finds this useful ...

public class StringMisc {

   // MARK: - Constants

   // This is used by the byteArrayToHexString() method
   private static let CHexLookup : [Character] =
      [ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F" ]


   // Mark: - Public methods

   /// Method to convert a byte array into a string containing hex characters, without any
   /// additional formatting.
   public static func byteArrayToHexString(_ byteArray : [UInt8]) -> String {

      var stringToReturn = ""

      for oneByte in byteArray {
         let asInt = Int(oneByte)
         stringToReturn.append(StringMisc.CHexLookup[asInt >> 4])
         stringToReturn.append(StringMisc.CHexLookup[asInt & 0x0f])
      }
      return stringToReturn
   }
}

Test case:

  // Test the byteArrayToHexString() method
  let byteArray : [UInt8] = [ 0x25, 0x99, 0xf3 ]
  assert(StringMisc.byteArrayToHexString(byteArray) == "2599F3")