Readme.md and XOR assignment - preferredName()

My first pull request.  Everything look good?
I may have gone overboard on trying to create something that does it all in one line?  Or maybe, even if it does work, it is still bad code because it is confusing to read??

You're the expert of course, and I will do per your request if this needs to be rewritten for clarity or any other reason...  but I was pretty sure it works good, and was trying to do it in the min number of lines.  I think I did that??