Mike Dalessio(Nokogiri核心开发人员的一半)给了我答案#nokogiri(irc.freenode.net).看起来Nokogiri CSS和XPath搜索都不支持正则表达式匹配.这是他如何使用Nokogiri搜索正则表达式的解决方案:

require 'rubygems'
require 'nokogiri'

value = Nokogiri::HTML.parse(<<-HTML_END)
  "
    
      
A
      
B
      
Bla
      
C
      
D
      

        
3
      
      

        
3
      
    
  "
HTML_END

# my_block is given
my_bl = "1"
# my_eq corresponds to this regex
my_eq = "[0-9]+"
# full regex to search for in node ids
full_regex = %r(eq-#{my_eq}_bl-#{my_bl})

filter_by_id = Class.new do
  attr_accessor :matches

  def initialize(regex)
    @regex = regex
    @matches = []
  end

  def filter(node_set)
    @matches += node_set.find_all { |x| x['id'] =~ @regex }
  end
end.new(full_regex)

value.css("div.foo:filter()", filter_by_id)
filter_by_id.matches.each do |node|
  puts node
end