Xquery to find the next to last item

Question

with xml something like:

<item > 
   <datapoint>5</datapoint>
</item>
<item > 
   <datapoint>4</datapoint>
</item>
<item > 
   <datapoint>6</datapoint>
</item>
<item > 
   <datapoint>8</datapoint>
</item>
<item > 
   <datapoint>9</datapoint>
</item>

And the number of items is not a fixed number. I am already retrieving the last() data point, however I now also need to grab the next to last data point. So in this example I need to separately return both the 8 and the 9.

Answer 1

This XQuery should work:

for $it in $file/item[position()=last() or position()=last()-1]
return $it/datapoint

Or, you could also use a shorter version:

for $it in $file/item[position()>=last()-1]
return $it/datapoint

Output is:

<datapoint>8</datapoint>
<datapoint>9</datapoint>