title: How to compare two NSDates: Which is more recent?
body: <p>I am trying to achieve a dropBox sync and need to compare the dates of two files. One is on my dropBox account and one is on my iPhone. </p>
  
  <p>I came up with the following, but I get unexpected results. I guess I'm doing something fundamentally wrong when comparing the two dates. I simply used the > &lt; operators, but I guess this is no good as I am comparing two NSDate strings. Here we go:</p>
  
  <pre><code>NSLog(@"dB...lastModified: %@", dbObject.lastModifiedDate); 
  NSLog(@"iP...lastModified: %@", [self getDateOfLocalFile:@"NoteBook.txt"]);
  
  if ([dbObject lastModifiedDate] &lt; [self getDateOfLocalFile:@"NoteBook.txt"]) {
      NSLog(@"...db is more up-to-date. Download in progress...");
      [self DBdownload:@"NoteBook.txt"];
      NSLog(@"Download complete.");
  } else {
      NSLog(@"...iP is more up-to-date. Upload in progress...");
      [self DBupload:@"NoteBook.txt"];
      NSLog(@"Upload complete.");
  }
  </code></pre>
  
  <p>This gave me the following (random &amp; wrong) output:</p>
  
  <pre><code>2011-05-11 14:20:54.413 NotePage[6918:207] dB...lastModified: 2011-05-11 13:18:25 +0000
  2011-05-11 14:20:54.414 NotePage[6918:207] iP...lastModified: 2011-05-11 13:20:48 +0000
  2011-05-11 14:20:54.415 NotePage[6918:207] ...db is more up-to-date.
  </code></pre>
  
  <p>or this one which happens to be correct:</p>
  
  <pre><code>2011-05-11 14:20:25.097 NotePage[6903:207] dB...lastModified: 2011-05-11 13:18:25 +0000
  2011-05-11 14:20:25.098 NotePage[6903:207] iP...lastModified: 2011-05-11 13:19:45 +0000
  2011-05-11 14:20:25.099 NotePage[6903:207] ...iP is more up-to-date.
  </code></pre>