title: How to get a single NSString character from an NSString
body: <p>I want to get a character from somewhere inside an NSString. I want the result to be an NSString.</p>
  
  <p>This is the code I use to get a single character at index it:</p>
  
  <pre><code>[[s substringToIndex:i] substringToIndex:1]
  </code></pre>
  
  <p>Is there a better way to do it?</p>