.. _number:

======
number
====== 

Converts a value or a node to a number

Description
~~~~~~~~~~~
The fn:number function constructs an xs:double value either from a node that 
contains a number, or from an atomic value. This function is useful for telling 
the processor to treat a node or value as a number, regardless of its declared 
type (if any). It returns the argument cast as an xs:double.

The difference between using the fn:number function and the xs:double 
constructor is that the fn:number function returns the value NaN in the case 
that the argument cannot be cast to a numeric value, whereas the xs:double 
constructor will raise an error.

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   :header-rows: 1

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

Examples
~~~~~~~~
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   * - **XPath**
     - **Results**
   * - number($priceDoc//prod[1]/price)
     - 29.99
   * - number($priceDoc//prod/price)
     - Error XPTY0004
   * - number($priceDoc//prod[1]/@currency)
     - NaN
   * - number('29,99')
     - 29.99
   * - number('ABC')
     - NaN
   * - number( () )
     - NaN
   * - $priceDoc//prod/price[number() > 35]
     - <price currency="USD">69.99</price> <price currency="USD">39.99</price>

See Also
~~~~~~~~

.. toctree::
   :titlesonly:
   :glob:

* :ref:`functx_is-a-number`.