Re: [xsl] Seek an XPath 2.0 expression that handles an empty text field, regardless of how it's represented in XML

["Sewell, David R. (drs2n) dsewell@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

The XPath you have is what I would probably use, only if there's any chance of 
creating pseudo-empty elements with whitespace only I would use normalize-space:

if (not(B) or normalize-space(B) eq '') then "do action" else "no action"

David

On Thu, 22 Sep 2016, Costello, Roger L. costello@xxxxxxxxx wrote:

> Hi Folks,
>
> I have a tab-delimited text file. Here is one row of the file:
>
> A 	B 	C
> foo		bar
>
> The value in field B is optional. In this particular row there is no value for B so it is empty.
>
> I could represent the text file in XML by creating an element for each field and then putting a wrapper element around the elements. For an empty field I could represent that by omitting the element. So here is one way to represent the row:
>
> <Row>
>    <A>foo</A>
>    <C>bar</C>
> </Row>
>
> Notice that I omitted the <B> element because the B field is empty.
>
> Alternatively, I could represent an empty field with an empty element:
>
> <Row>
>    <A>foo</A>
>    <B/>
>    <C>bar</C>
> </Row>
>
> Notice the empty <B> element.
>
> I want an XPath 2.0 expression that outputs "do action" if the B field is empty, regardless of which of the two XML representations is used. This XPath expression seems to work:
>
> if (not(B) or B eq '') then "do action" else "no action"
>
> Is there a better (simpler, more efficient, more future-proof) XPath 2.0 expression?
>
> /Roger

--
David Sewell
Manager of Digital Initiatives
The University of Virginia Press
Email: dsewell@xxxxxxxxxxxx   Tel: +1 434 924 9973
Web: http://www.upress.virginia.edu/rotunda