title: Regex to validate the number of pipe delimited items
body: <p>I've got a string which is pipe '|' delimited. I need a regex to validate the number of items, based on the pipe character. So a regex which will do the following:</p>
  
  <p>If the max number of items is three:</p>
  
  <p>asdfasdf|asdfasdf|asdfasdf = VALID</p>
  
  <p>asdfasdf|asdfasdf|asdfasdf|asdfasf = Not Valid</p>
  
  <p>Also, this string may be empty.</p>
  
  <p>Any help would be much appreciated</p>
  
  <p>Regards</p>