title: NSMutableArray append NSMutableArray
body: <p>I am trying to set the contents of my allArticlesArray, and then append the array with additional objects. Here is a snippet from my code to do so:</p>
  
  <pre><code>[self.allArticlesArray setArray:newsArray];
  [self.allArticlesArray addObjectsFromArray:sportsArray];
  </code></pre>
  
  <p>newsArray and sportsArray are non-null (they each have five items), however, after this code runs, allArticlesArray is null. I am using ARC. What am I doing wrong?
  Thanks! </p>