title: How to merge and diff lists in Scala?
body: <p>How do I perform an operation that checks the IDs and removes the different elements of the first list and adds the different elements of the second list?</p>
  
  <p>The letters are a Entity Id. The numbers are a object reference in memory. </p>
  
  <pre><code>List 1: A:1, B:2, C:3, D:4, E:5
  List 2: B:6, C:7, E:8, F:9
  
  RemovedElements: A:1, D:4
  InvalidElements: B:6, C:7, E:8
  ResultList: B:2, C:3, E:5, F:9
  </code></pre>
  
  <p>Does anyone know if there is any function that performs this operation?</p>