title: Find differences and missing elements from multiple arrays
body: <p>I have an array that contains <code>n</code> arrays and each of these arrays contain a different number of string elements.</p>
  
  <p>Each string contains a key word like <code>evar#</code>, <code>event#</code>, <code>prop#</code> (where <code>#</code> is a number).</p>
  
  <p>I need to do the following:</p>
  
  <ul>
  <li>return all the key words from a string that is different with at least one of the other arrays </li>
  <li>return the key words that does not exist in at least one of the other arrays.</li>
  </ul>
  
  <p>Here is an example with an array that contains 3 arrays:</p>
  
  <pre><code>[
      [
          "overwrite value of evar1 with page_url_query 'int_cmp'", 
          "set event1 to custom value '1'", 
          "set event2 to custom value '1'", 
          "overwrite value of evar2 with page_url", 
          "overwrite value of evar3 with contextdata.user_id", 
          "set event4 to eventid", 
          "set event3 to eventid"
  
      ], 
      [
          "overwrite value of prop3 with contextdata.phase", 
          "overwrite value of prop2 with contextdata.room", 
          "set event1 to custom value '1'", 
          "set event2 to eventid", 
          "overwrite value of evar5 with contextdata.queue", 
          "set event4 to eventid", 
          "overwrite value of evar6 with contextdata.audience", 
          "set event3 to eventid",
          "set event5 to custom value '1'"
      ], 
      [
          "overwrite value of evar4 with contextdata.no_challenges", 
          "overwrite value of prop3 with contextdata.user_type", 
          "overwrite value of evar7 with contextdata.interaction", 
          "set event2 to custom value '1'", 
          "set event3 to eventid",
          "set event4 to eventid", 
          "set event1 to custom value '1'", 
          "set event5 to custom value '1'"
      ]
  ]
  </code></pre>
  
  <p>And the response should contain the following array: </p>
  
  <pre><code>[evar1, event2, evar2, evar3, prop3, prop2, evar6, event5, evar4, evar7]
  </code></pre>
  
  <p>Please let me know if I need to provide more information. I'm open to any suggestions...</p>
  
  <p>LATER EDIT:</p>
  
  <p>I implemented a solution, but I think that it needs some optimization. I would appreciate if someone helps me with that...</p>