title: how can i convert NSString to String
body: <p>Im trying to convert a NSString from a text field to a standard String so that I can check if it contains a certain character. </p>
  
  <p>I have tried</p>
  
  <pre><code>var nSStringText = textField.text! as NSString
  var stringText = nSStringText as String
  
  </code></pre>
  
  <pre><code>output
  
  'NSString' is not convertible to 'String'
  </code></pre>