title: How does UITableViewRowAnimationAutomatic determine which animation to use?
body: <p>The iOS 5 SDK introduced a new animation type for table cell insertions and deletions: <code>UITableViewRowAnimationAutomatic</code>. <a href="https://developer.apple.com/documentation/uikit/uitableviewrowanimation/uitableviewrowanimationautomatic" rel="nofollow noreferrer">Apple's documentation</a> for this value simply states:</p>
  
  <blockquote>
    <p>The table view chooses an appropriate animation style for you.</p>
  </blockquote>
  
  <p>So, err, how does this work, exactly? What factors does the table view take into account? The length of the table? The visible data? The phase of the moon?</p>