FunctX XQuery Function Library > Numbers > Comparing >

functx:is-a-number

Whether a value is numeric

Description

The functx:is-a-number function returns true if the value is number (can be cast to a numeric type) and is not the value NaN. If the argument is the empty sequence or a zero-length string, it returns false.

Arguments and Return Type

XQuery Function Declaration

declare namespace functx = "http://www.functx.com";
declare function functx:is-a-number
  ( $value as xs:anyAtomicType? )  as xs:boolean {

   string(number($value)) != 'NaN'
 } ;

Examples

<in-xml>
   <a>123</a>
   <b>abc</b>
</in-xml>

functx:is-a-number('123')

true

functx:is-a-number(123)

true

functx:is-a-number('  123  ')

true

functx:is-a-number('')

false

functx:is-a-number('123abc')

false

functx:is-a-number('NaN')

false

functx:is-a-number($in-xml/a)

true

functx:is-a-number($in-xml/b)

false

See Also

History