title: array_unique with two arrays
body: <p>I have two arrays of the same length <code>($search_type, $search_term)</code>.  I want to remove any duplicates in the sense of there being searches that have the same type and search term (ie <code>$search_type[$a] == $search_type[$b] &amp;&amp; $search_term[$a] == $search_term[$b]</code>).  </p>
  
  <p>I'm aware that I could write this using loops, was wondering if there's a simpler (but equally efficient) way that takes advantage of built in functions?</p>