title: Convert String to date Objective-C
body: <p>I have seen the other answer and question but i didn't find any useful answer for me.
  I have a string like <code>2014-10-07T07:29:55.850Z</code> and I want to have a date to compare each other.
  If I use this code:</p>
  
  <pre><code> NSString *fullDate = payload[@"sent_ts"];
   NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
   dateFormat setDateFormat:@"yyyy-MM-ddTHH:mm:ss.SSSZ"];
   NSDate *date = [dateFormat dateFromString:fullDate];
  </code></pre>
  
  <p>My date is nil. Why?</p>