Nokogiri recursively get all children

问题

The Problem

I am running some statistics against various URLS. I want to find the top level element with the most concentrated number of children. The method that I would like to follow is to identify all top level elements and then determine what percentage of all the elements on the page belong to it.

Goal

Recursively get all children of a given element.

Inputs: a Nokogiri Element

Outputs: an array of Nokogiri Elements OR the count of total number of children

Setup

Ruby 1.9.2
Nokogiri gem

What I ended up coming up with (this works, but isn't as pretty as my chosen answer below)

getChildCount(elem)
    children = elem.children
    return 0 unless children and children.count > 0
    child_count = children.count
    children.each do |child|
        child_count += getChildCount(child)
    end
    child_count
end

回答1:

the traverse method yields the current node and all children to a block, recursively.

# if you would like it to be returned as an array, rather than each node being yielded to a block, you can do this
result = []
doc.traverse {|node| result << node }
result

# or, 
require 'enumerator'
result = doc.enum_for(:traverse).map

回答2:

# Non-recursive
class Nokogiri::XML::Node
  def descendant_elements
    xpath('.//*')
  end
end

# Recursive 1
class Nokogiri::XML::Node
  def descendant_elements
    element_children.map{ |kid|
      [kid, kid.descendant_elements]
    }.flatten
  end
end

# Recursive 2
class Nokogiri::XML::Node
  def descendant_elements
    kids = element_children.to_a
    kids.concat(kids.map(&:descendant_elements)).flatten
  end
end

来源：https://stackoverflow.com/questions/10076190/nokogiri-recursively-get-all-children

标签

ruby

xhtml

nokogiri