title: Swift: Unique Int id from String
body: <p>I am using Parse which has an preload User table in the database. I want from each user a unique userId (Int). Parse's objectId is unique but not an Int and username is a String. Username is unique for each user , so can I somehow convert each username into a number ?</p>
  
  <p>I tried .toInt() , Int() but I got nothing.  </p>
  
  <p>WHY :<br>
  I have an existing table with user's ratings (movies) and I want to extent this table with more ratings. The userId field is a Number value so I must keep it this way.</p>