title: NSPredicate filter by letter
body: <p>How do you make an NSPredicate that finds all objects in an array that contain a certain letters? </p>
  
  <pre><code>NSMutableArray *testArray = [[NSMutableArray alloc] initWithObjects:@"abc",@"cba", @"bca", nil];
  
  NSPredicate *p = [NSPredicate predicateWithFormat:@"SELF contains[cd] %@",@"abc"];
  
  NSMutableArray *result = (NSMutableArray *)[testArray filteredArrayUsingPredicate: p];
  </code></pre>
  
  <p>Result only contains one object, @"abc"... I want it to catch all words that have "abc" in them. (e.g "cba", "cba", "lllllllllbbacllllll" etc).. </p>