.. _avg:

===
avg
=== 

The average of a sequence of values

Description
~~~~~~~~~~~
The fn:avg function averages a sequence of values. The $arg sequence can contain 
a mixture of numeric and untyped values. Numeric values are promoted as 
necessary to make them all the same type. Untyped values are cast as numeric 
xs:double values.

The function can also be used on duration values, so the $arg sequence can 
contain all xs:yearMonthDuration values or all xs:dayTimeDuration values (but 
not a mixture of the two). 

Special care should be taken with any "missing" values when using the fn:avg 
function. See functx:avg-empty-is-zero for more information. 

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

   * - **Parameters**
     - **Description**
   * - arg:numeric()
     - 

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

   * - **XPath**
     - **Results**
   * - avg( (1, 2, 3, 4, 5) )
     - 3
   * - avg( (1, 2, 3, (), 4, 5) )
     - 3
   * - avg((xs:yearMonthDuration('P4M'), xs:yearMonthDuration('P6M') ) )
     - P5M
   * - avg($ordDoc//item/@quantity)
     - 1.1666666666666667
   * - avg( () )
     - ()
   * - avg($ordDoc//item/@dept)
     - Error FORG0001

See Also
~~~~~~~~

.. toctree::
   :titlesonly:
   :glob:

* :ref:`functx_avg-empty-is-zero`.
* :ref:`sum`.
* :ref:`count`.