# Using XPath: find last text node of each paragraph under the root node

**URL:** <https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362>\
**Category:** Ruby\
**Created:** [November 3, 2008, 5:50am UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362 "2008-11-03T05:50:33Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Diego](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f04885/32.png) [@Diego](https://www.ruby-forum.com/u/Diego)\
**Post date:** [November 3, 2008, 5:50am UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362/1 "2008-11-03T05:50:33Z")

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I want to trim trailing whitespace at the end of all XHTML paragraphs.  
I am using the REXML library.

Say I have the following in a valid XHTML file:

hello world a

Hi there

The End

I want to end up with this:

hello world a

Hi there

The End

So I was thinking what I could use XPath to get just the text nodes  
that I want, then just trim the text, which would allow me to end up  
with what I want (previous).

I started with the following XPath: //root/p/child::text()

Of course, the problem here is that it returns all text nodes that are  
children of all p-tags. Which is this:

'hello ’  
’ a ’  
'Hi there ’  
'The End ’

Trying the following XPath gives me the last text node of the last  
paragraph. Not the last text node of each paragraph that is a child of  
the root node.

//root/p/child::text()[last()]

This only returns: 'The End ’

What I would like to get from the XPath is therefore:

’ a ’  
'Hi there ’  
'The End ’

I have tried //root//p/child::text()[last()] on other XPath parsers,  
and it works. Could just be a bug (or different interpretation of the  
rules) by REXML?

Cheers, Diego

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<div class="post-metadata">

**Author:** ![Diego](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f04885/32.png) [@Diego](https://www.ruby-forum.com/u/Diego)\
**Post date:** [November 3, 2008, 11:41am UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362/2 "2008-11-03T11:41:47Z")

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2008/11/3 Diego [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> Of course, the problem here is that it returns all text nodes that are
> 
> I have tried //root//p/child::text()[last()] on other XPath parsers,  
> and it works. Could just be a bug (or different interpretation of the  
> rules) by REXML?

Could well be both. When I try ‘//p/text()[last()]’ I get only the  
last node of the whole document. The issue seems to be the binding of  
last() i.e. which collection it references or when it is applied. I  
lean towards the bug variant.

One workaround would be to use a two step approach, i.e. first select  
all

and then the last text:

irb(main):062:0\> doc.elements.each(‘//p’){|x|  
REXML::XPath.each(x,‘text()[last()]’){|t|p t}}  
" a "  
"Hi there "  
"The End "  
=\> [

… \</\>,

… \</\>,

… \</\>]

Kind regards

robert

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<div class="post-metadata">

**Author:** ![Diego](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f04885/32.png) [@Diego](https://www.ruby-forum.com/u/Diego)\
**Post date:** [November 3, 2008, 5:02pm UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362/3 "2008-11-03T17:02:03Z")

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> I have tried //root//p/child::text()[last()] on other XPath parsers,  
> and it works. Could just be a bug (or different interpretation of the  
> rules) by REXML?

Sounds like a bug to me too. Is there a reason you don’t want to use a  
parser like libxml-ruby, which is fully XPath 1.0 compliant (and will  
give you a speed boost as well)?

– Mark.

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<div class="post-metadata">

**Author:** ![Diego](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f04885/32.png) [@Diego](https://www.ruby-forum.com/u/Diego)\
**Post date:** [November 3, 2008, 6:15pm UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362/4 "2008-11-03T18:15:46Z")

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On 03.11.2008 16:59, Mark T. wrote:

> Is there a reason you don’t want to use a  
> parser like libxml-ruby, which is fully XPath 1.0 compliant (and will  
> give you a speed boost as well)?

I can’t speak for Diego but I use REXML because it’s there and I do not  
have to satisfy serious performance requirements when doing XML  
processing.

Cheers

robert

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<div class="post-metadata">

**Author:** ![Diego](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f04885/32.png) [@Diego](https://www.ruby-forum.com/u/Diego)\
**Post date:** [November 5, 2008, 12:05am UTC](https://www.ruby-forum.com/t/using-xpath-find-last-text-node-of-each-paragraph-under-the-root-node/152362/5 "2008-11-05T00:05:55Z")

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@Robert: As you suggest, a work around is in order. I had a look at  
other XPath implementations and they were returning what I originally  
expected. Just not REXML. At least now I am sure it’s not just me. 🙂

@Mark: I would consider something other than REXML if (for example) I  
maybe had performance issues using a work around. Or if there was not  
easy work around. As Robert commented, I use it because it’s there and  
had not run in to any real problems prior to this. So I was happy with  
it. Certainly if it was a show-stopper then I would switch to  
something else. But thanks for the recommendation. Something to keep  
in mind.

Cheers.