On 2009-06-05, Martin Honnen <mahotrash@y...> wrote:
> Mario Splivalo wrote:
>> Here is my XML document:
>> 
>> <a>
>>   <b>1</b>
>>   <b>2</b>
>>   <b></b>
>>   <b>3</b>
>> </a>
>> 
>> When I execute this XPath query against it: /a/b/text()
>> 
>> I get only 1, 2 and 3:
>> 
>> mario@mike:~$ echo "<a><b>1</b><b>2</b><b></b><b>3</b></a>" | xpath -e '/a/b/@id'
>
> Why /a/b/@id? There is no 'id' attribute in there at all.

A typo, I'd say :) This is the correct Xpath query:

... | xpath -e '/a/b/text()'

>
>
>> Is there a way to extract that NULL-valued node?
>
> There is an empty 'b' element in there. If you want to select all 'b' 
> elements then use the XPath
>    /a/b

The 'trouble' is that I get XML portions, and I wanted 'clean' strings. I
guess I could do another XPath query on return values, and then easily see
wich ones are 'empty'.

> if you only want the empty 'b' elements then use
>    /a/b[not(node())]

That does me no good because I need to know on (in?) which position the
empty element is. My actuall XML (shoul've written that in the OP) looks
like this:

<itemList>
  <item fieldName="name">Mario</item>
  <item fieldName="age">29</item>
  <item fieldName="height"></item>
</itemList>

What I'm trying to get is a rowset or table, since I'm doing this from
postgres. So, my table would look like this:

fieldName      fieldValue
name           Mario
age            29
height         NULL

The idea was to have two XPath queries on the original XML. First one
('/itemList/item/@fieldName') would extract all the attributes, and second
one would extract all the 'values' ('/itemList/item/text()'). Now I guess
I'll have to extract the nodes, as you've suggested, and then for each node
chech if it's empty or not.

	Mike
-- 
"I can do it quick. I can do it cheap. I can do it well. Pick any two."

Mario Splivalo
majk@f...