title: Regular Expressions in Objective-C and Core Data
body: <p>Is there a guide to using regular expressions in objective c?
  Specifically what to type into the "Reg. Ex." field in a core data property?</p>
  
  <p>In particular, how to limit input to a set amount of numbers/letters only, and for UK Post Codes?</p>
  
  <p>Thanks!</p>