Question

Here is a piece of XML document:

<book category="WEB">
    <title lang="en">XQuery Kick Start</title>
    <author>James McGovern</author>
    <author>Per Bothner</author>
    <author>Kurt Cagle</author>
    <author>James Linn</author>
    <author>Vaidyanathan Nagarajan</author>
    <year>2003</year>
    <price>49.99</price>
</book>    

I’m asked to find out the authors whose lastname begin with a capital “C” using XPath. It’s simple in this question because there is only one qualified and I can just use the function substring-after() after a whitespace and then check whether it begins with “C”. But there is also a possibility that this guy has a very long name, thus middlename can appear, such as Kurt Van Persie Cagle. How can I strip out exactly the substring after the last whitespace?

Please explain and use the functions in XPath.

Answer 1

You can use “mess” XPath, e.g. you have limit of 4 word in author:

//author[
    (starts-with(substring-after(., ' '), 'C') and not(contains(substring-after(., ' '), ' ')))
    or
    (starts-with(substring-after(substring-after(., ' '), ' '), 'C') and not(contains(substring-after(substring-after(., ' '), ' '), ' ')))
    or
    (starts-with(substring-after(substring-after(substring-after(., ' '), ' '), ' '), 'C') and not(contains(substring-after(substring-after(substring-after(., ' '), ' '), ' '), ' ')))
]

---

Input:

<book>
    <author>James McGovern</author>
    <author>Per Bothner</author>
    <author>Kurt Cagle</author>
    <author>James Linn</author>
    <author>James Linn</author>
    <author>Kurt Van Persie Cagle</author>
</book>

Above XPath will select 2 authors: Kurt Cagle and Kurt Van Persie Cagle. You can extend this XPath to match authors having 5 words and so on… 🙂