title: Subarray from NSMutableArray
body: <p>I have a NSMutableArray with many objects.
  Can i extract a subarray from index range 'i' to 'j' directly?
  Yeah i know i can do a loop and use objectAtIndex:x and extract each object to a new.</p>
  
  <p>I need to call a method which input is an array and want to use this array only with validate data.</p>