.. _functx_avg-empty-is-zero:

========================
functx:avg-empty-is-zero
======================== 

The average, counting "empty" values as zero

Description
~~~~~~~~~~~
The functx:avg-empty-is-zero function returns the average of the non-empty 
values in $values, over the number of nodes provided in $allNodes. This is 
useful for performing calculations where you want "missing" elements and/or 
attribute values to count as zero rather than not being included in the average 
at all.

.. list-table::
   :widths: 40 60
   :header-rows: 1

   * - **Parameters**
     - **Description**
   * - values:numeric()
     - the values to be averaged
   * - allNodes:node()
     - the sequence of all nodes to find the average over

Examples
~~~~~~~~
.. list-table::
   :widths: 25 25 50
   :header-rows: 1

   * - **XPath**
     - **Results**
     - **Explanation**
   * - functx:avg-empty-is-zero($in-xml//price/@discount, $in-xml//price)
     - 4
     - The average discount for the prices is 4, if you want the discount on the 3rd and 4th prices to be counted as zero. Using fn:avg($in-xml//price/@discount) function would have raised an error because the discount on the 4th price is not a valid number. If the 4th price did not have a discount attribute, it would return 8.
.. list-table::
   :widths: 50 50
   :header-rows: 1

   * - **XPath**
     - **Results**
   * - functx:avg-empty-is-zero($in-xml//price/@discount, $in-xml//price)
     - 4

See Also
~~~~~~~~

.. toctree::
   :titlesonly:
   :glob:

* :ref:`avg`.