title: XSLT: Finding last occurence in a string
body: <p>Given a form number like:</p>
  
  <pre><code>ABC_12345_Q-10
  </code></pre>
  
  <p>I want to end up with:</p>
  
  <pre><code>ABC12345
  </code></pre>
  
  <p>So I need to find the position of the second underscore</p>
  
  <p>Note that there is no standard pattern or length to any of the "sections" between the underscores (so I cannot use substring to simply eliminate the last section).</p>
  
  <p>xPath 2.0 solutions are okay.</p>