hpricot：An Hpricot Showcase：Hpricot Challenge：Selecting the value of an element's attribute using just XPath

ほぼ、まんま

require "hpricot"

X =<<EOS
<div id="foo">
    Fnord!
</div>
EOS

doc = Hpricot(X)
#p (doc/"div[@id]").get_attribute("id")
p (doc/"div[@id]").first.get_attribute("id")
p (doc/"div").first.get_attribute("id")
p (doc/"div[@id]").first

で、

"foo"
"foo"
{elem <div id="foo"> "\n    Fnord!\n" </div>}