.. _functx_if-absent:

================
functx:if-absent
================ 

The first argument if it is not empty, otherwise the second argument

Description
~~~~~~~~~~~
The functx:if-absent function is useful for providing default values in case a 
data item is absent. It checks if the $arg argument is the empty sequence, and 
if it is, it returns the value $value. Otherwise, it returns the typed value of 
$arg itself. Note that an element or attribute is not considered "absent" if it 
contains a zero-length string; only if it does not exist at all.

Note: This function is similar to the eg:if-absent function provided in the 
XQuery 1.0 and XPath 2.0 Functions and Operators document. However, this 
function differs in that it supports attribute nodes and atomic values.

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

   * - **Parameters**
     - **Description**
   * - arg:item()
     - the item(s) that may be absent
   * - value:item()
     - the item(s) to use if the item is absent

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

   * - **XPath**
     - **Results**
   * - data(functx:if-absent($in-xml//price[1]/@discount, 0))
     - 10.00
   * - data(functx:if-absent($in-xml//price[3]/@discount, 0))
     - 0
   * - data(functx:if-absent($in-xml//price[4]/@discount, 0))
     - zero-length untyped value

See Also
~~~~~~~~

.. toctree::
   :titlesonly:
   :glob:

* :ref:`functx_if-empty`.
* :ref:`functx_all-whitespace`.
* :ref:`empty`.