How to get all nodes or elements in a html or xml document using Ruby, Nokogiri and xpath.

all_nodes.rb

require 'rubygems'
require 'nokogiri'

xml =  <<EOF
<Guide>
  <Master>
    <Part>12345</Part>
    <Sub>
       <Name>A</Name>
    </Sub>
    <Sub>
       <Name>B</Name>
    </Sub>
  </Master>
  <Master>
    <Part>XYZABC</Part>
    <Sub>
       <Name>A</Name>
    </Sub>
    <Sub>
       <Name>C</Name>
    </Sub>
  </Master>
</Guide>
EOF

doc = Nokogiri::XML::DocumentFragment.parse(xml)

puts doc.xpath(".//*").size   # => Should be 13

doc.xpath(".//*").each do | node |
  puts node.name
end