title: Transform XML with missing element values into wide CSV format through XSLT
body: <p>How would you efficiently transform this XML document  </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" ?&gt;
  &lt;Document&gt;
    &lt;Person&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Height&lt;/Name&gt;
        &lt;Value&gt;172&lt;/Value&gt;
      &lt;/Entry&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Weight&lt;/Name&gt;
        &lt;Value&gt;73&lt;/Value&gt;
      &lt;/Entry&gt;
    &lt;/Person&gt;
    &lt;Person&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Height&lt;/Name&gt;
        &lt;Value&gt;180&lt;/Value&gt;
      &lt;/Entry&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Weight&lt;/Name&gt;
        &lt;Value&gt;70&lt;/Value&gt;
      &lt;/Entry&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Age&lt;/Name&gt;
        &lt;Value&gt;30&lt;/Value&gt;
      &lt;/Entry&gt;    
    &lt;/Person&gt;
    &lt;Person&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Height&lt;/Name&gt;
        &lt;Value&gt;176&lt;/Value&gt;
      &lt;/Entry&gt;
      &lt;Entry&gt;
        &lt;Name&gt;Age&lt;/Name&gt;
        &lt;Value&gt;25&lt;/Value&gt;
      &lt;/Entry&gt;    
    &lt;/Person&gt;  
  &lt;/Document&gt;  
  </code></pre>
  
  <p>into this CSV file?</p>
  
  <pre><code>"Height","Weight","Age"
  "172","73",""
  "180","70","30"
  "176","","25"
  </code></pre>
  
  <p>It is different from <a href="https://stackoverflow.com/questions/32329277/xml-to-csv-using-xslt-with-missing-elements">this question</a> in which the missingness (or variation) is in elements, not in element values. </p>