NodeSet#text 总是返回一个字符串(否则它可能被称为 NodeSet#texts).Nokogiri 文档不是很好，如有疑问，请查看源代码:

NodeSet#text always returns a string (otherwise it would probably be called NodeSet#texts). Nokogiri docs are not so great, when in doubt check the source code:

  # lib/nokogiri/xml/node_set.rb
  def inner_text
    collect{|j| j.inner_text}.join('')
  end
  alias :text :inner_text

获取文本数组:nodes.map(&:text)