title: Compare 2 NSMutableArrays and remove duplicate records
body: <p>I have 2 <code>NSMutableArray</code>s. They are:</p>
  
  <pre><code>allStudentsMutableArr
  selectedStudentsMutableArr
  </code></pre>
  
  <p><code>allStudentsMutableArr</code> contains all the <code>Student</code> objects and it has around 100 objects saved in it. Whereas, <code>selectedStudentsMutableArr</code> only contains 10 <code>Student</code> records saved in it.</p>
  
  <p>Now i need to compare the 2 MutableArrays and remove all objects from <code>allStudentsMutableArr</code> that's present in <code>selectedStudentsMutableArr</code> mutable array. How can i do this ?</p>