title: Parse.com: How to properly check if a field is empty?
body: <p>I ask this in the context of a iOS / Swift  app:</p>
  
  <p>When retrieving with a query an object from Parse, I used to check for empty fields by checking them against nil. if != nil.... then do this etc etc....</p>
  
  <p>Apparently, this is not the proper way to do this, because even if a field is empty on Parse, it is NOT considered nil by swift. </p>
  
  <p>So what to to check for to determine if a field is empty or not, and for the various Parse supported types: strings, Number, Array.....?</p>
  
  <p>Edit: there are answers for objective-c that don't work in swift where unless value is a boolean you MUST compare it against nil (which cause issue here) or something else to see if it exists or not.</p>