title: Objective-C "if not equal or" statement not working
body: <p>I'm relatively new to Objective-C.</p>
  
  <p>I'm trying to construct an <code>if</code> statement to check if something is not equal to 'a' nor 'b' and when I add the "or" part, it doesn't seem to work for either statement. If I remove the "or", it works for one or the other.</p>
  
  <p>This code works (for one statement):</p>
  
  <pre><code>NSString *source = metaItem.stringValue;
  NSString *baddata = @"a";
  NSString *baddata2 = @"b";
  if (![source isEqualToString:baddata])
  {
      if(![source isEqualToString:self.songInfo.text])
      {
          self.songInfo.text = [source stringByAppendingString:@"  "];                
      }
  }
  </code></pre>
  
  <p>Equally, if I change <code>baddata</code> to <code>baddata2</code> it also works correctly. But if I change it to this (to detect either) neither of them are detected:</p>
  
  <pre><code>if (![source isEqualToString:baddata] || ![source isEqualToString:baddata2])
  </code></pre>
  
  <p>Is the <code>if</code> line incorrect? Do I need to use something like "nor" and if so, what is the syntax?</p>