title: Objective-C Find the most commonly used words in an NSString
body: <p>I am trying to write a method:</p>
  
  <pre><code>- (NSDictionary *)wordFrequencyFromString:(NSString *)string {}
  </code></pre>
  
  <p>where the dictionary returned will have the words and how often they were used in the string provided.  Unfortunately, I can't seem to find a way to iterate through words in a string to analyze each one - only each character which seems like a bit more work than necessary. Any suggestions?</p>