title: NSMutableArray remove duplicate items
body: <pre><code> NSLog(@"Ci sono %d categorie",category.count);
   for(int c=0; c&lt;category.count; c++){
   CategoryArray * element =[category objectAtIndex:c];
   NSLog(@"******************************");
   NSLog(@"Titolo %@",element.label);
   NSLog(@"Source %@",element.url);
   NSLog(@"******************************");
   [element release];
  </code></pre>
  
  <p>This is my code! I need to remove all duplicates array... I use this code but I don't understand why it doesn't work.</p>
  
  <pre><code>uniquearray = [[NSSet setWithArray:category] allObjects];
  </code></pre>