XPath get the max value

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

beachboy - 27 Apr 2006 09:08 GMT

can we get the max value of element from xpath

e.g: Xpath Query Expression: /Books/Book[@id='3'] to select XMLNode which id
is "3"

Can I use Xpath to get the MAX Book id?

Thanks in advanced.

Reply to this Message

Martin Honnen - 27 Apr 2006 13:27 GMT

> can we get the max value of element from xpath
>
> e.g: Xpath Query Expression: /Books/Book[@id='3'] to select XMLNode which id
> is "3"
>
> Can I use Xpath to get the MAX Book id?

This XPath expression

/Books/Book[not(@id <= preceding-sibling::Book/@id) and not(@id <=
following-sibling::Book/@id)]

selects the Book element with the maximum id attribute value.

If you want to select the attribute itself then use

/Books/Book/@id[not(. <= ../preceding-sibling::Book/@id) and not(. <=
../following-sibling::Book/@id)]

Signature

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

Reply to this Message

beachboy - 28 Apr 2006 02:54 GMT

Thanks Martin,

I want to clarify my understanding..

I can get a XmlNode which has a max id attribute value for below syntax:
XmlNode node = doc.SelectSingleNode( /Books/Book[not(@id <=
preceding-sibling::Book/@id) and not(@id <= following-sibling::Book/@id)] )

but how to implement below expression? what type will return? XmlNode or
just a value of id
/Books/Book/@id[not(. <= ../preceding-sibling::Book/@id) and not(. <=
../following-sibling::Book/@id)]

Thanks again!!!

> > can we get the max value of element from xpath
> >
[quoted text clipped - 14 lines]
> /Books/Book/@id[not(. <= ../preceding-sibling::Book/@id) and not(. <=
> ../following-sibling::Book/@id)]

Reply to this Message

Martin Honnen - 28 Apr 2006 12:53 GMT

> but how to implement below expression? what type will return? XmlNode or
> just a value of id
> /Books/Book/@id[not(. <= ../preceding-sibling::Book/@id) and not(. <=
> ../following-sibling::Book/@id)]

That XPath expression selects attribute nodes with name id. Thus with
SelectSingleNode you will get one attribute node or null, with
SelectNodes you will get a node list with attribute nodes.

Signature

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

Reply to this Message

XPath get the max value

Free Magazines