title: Why do we still use NSDictionary and NSArrays in swift ios applications?
body: <p>I see a lot of code for swift ios tutorials on the internet still using the old <code>objective-c</code> data types like  <code>NSDictionary</code> and <code>NSArrays</code> instead of using the modern <code>Array</code> and <code>Dictionary</code> data types that come with Swift. </p>
  
  <p>Most often I see a lot of type casting going on using <code>as?</code> etc. I have seen this mostly in examples involving <code>json</code> parsing from a webservice.</p>
  
  <p>So why is this? Is this because swift isn't fully compatible withe cocoa touch apis yet? Or is there another reason like performance?</p>