title: How to remove duplicate elements inside an array - swift 3
body: <p>I want to remove duplicate elements from an array. there are many answers in stack overflow but for swift 3. </p>
  
  <p>my array:</p>
  
  <pre><code>var images = [InputSource]()
  ... // append to array
  </code></pre>
  
  <p>how to remove duplicate elements from this array?</p>
  
  <p>Is there any native api from swift 3 ?</p>