.. _functx_update-attributes:

========================
functx:update-attributes
======================== 

Updates the attribute value of an XML element

Description
~~~~~~~~~~~
The functx:update-attributes function takes one or more XML element nodes, along 
with a sequence of attribute names and a sequence of attribute values, and 
returns a newly constructed element with those attributes updated. The attribute 
names and values are positionally related, i.e. the first attribute name 
corresponds to the first attribute value, the second name to the second value, 
etc. It leaves all the original attributes and content of the element, except 
that if it already has an attribute with the same name of one of $attrNames, its 
value is updated to match the corresponding value in $attrValues. Unlike the 
functx:add-or-update-attributes function, if the attribute did not previous 
exist on the element, it is not added.

Each name must be specified as an xs:QName value. QNames can be constructed with 
calls to the xs:QName type constructor or the fn:QName function, as shown in the 
examples. 

The functx:update-attributes function takes one or more XML element nodes, along 
with an attribute name and value, and returns a newly constructed element with 
that attribute's value updated (and all the same content and attributes that 
existed on the original element.) If the attribute did not previous exist on the 
element, it is not added.

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   :widths: 40 60
   :header-rows: 1

   * - **Parameters**
     - **Description**
   * - elements:element()
     - the element(s) for which you wish to update the attribute
   * - attrNames:string()
     - the name(s) of the attribute(s) to add
   * - attrValues:string()
     - the value(s) of the attribute(s) to add

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

   * - **XPath**
     - **Results**
   * - functx:update-attributes($in-xml/a, xs:QName('att1'), 123)
     - <a att1="123">x</a>
   * - functx:update-attributes($in-xml/a, (xs:QName('att1'),xs:QName('att2')), (1,2))
     - <a att1="1">x</a>
   * - functx:update-attributes($in-xml/b, xs:QName('att1'), 123)
     - <b>x</b>
   * - functx:update-attributes($in-xml/c, QName('http://new','att1'), 123)
     - <c xmlns:new="http://new" new:att1="123">x</c>

See Also
~~~~~~~~

.. toctree::
   :titlesonly:
   :glob:

* :ref:`functx_add-attributes`.
* :ref:`functx_copy-attributes`.
* :ref:`functx_remove-attributes`.