title: How to convert Int to String.CharacterView.Index
body: <p>This is driving me nuts.</p>
  
  <p>In Swift 2.2, it makes it impossible to subscript <code>String</code> with <code>Int</code>. For example:</p>
  
  <pre><code>let myString = "Test string"
  let index = 0
  let firstCharacter = myString[index]
  </code></pre>
  
  <p>This will result with a compile error, saying </p>
  
  <blockquote>
    <p>'subscript' is unavailable: cannot subscript String with an Int, see the documentation comment for discussion</p>
  </blockquote>
  
  <p>One workaround I see is to convert integer to the index type, but I can't figure out how..</p>