title: What is the proper way to check if a Boolean key exists in NSUserdefaults/UserDefaults
body: <p>Which of the two examples below is best for checking if a <code>boolean</code> key exists in <code>NSUserdefaults</code>?   </p>
  
  <p><strong>1- Is this acceptable?</strong></p>
  
  <pre><code>if NSUserDefaults.standardUserDefaults().boolForKey("myKey"){
     print("Key Does Exist")
  }
  </code></pre>
  
  <p><strong>2- Is this the preferred way?</strong></p>
  
  <pre><code>if (NSUserDefaults.standardUserDefaults().objectForKey("myKey") != nil) {
       print("Key Does Exist")
  }
  </code></pre>