Getting text value in closest preceding sibling by class with Mechanize/Nokogiri - ruby

Question

Currently I'm looping over table rows and getting values from a td, putting them in a sorted hash identified by a value in a sibling td:
Ruby snippet
#counts = Hash.new
agent.page.search('.child').each do |child|
#counts[child.css('td')[0].text.strip!] = child.css('td')[1].text.gsub(/,/,'').to_i
end
puts #counts.sort_by{|k,v| v}.reverse.to_h
HTML structure
<tr class="parent">
<td class="info">Type</td>
<td>12,000</td>
</tr>
<tr class="child">
<td class="info">Sub Type</td>
<td>9,000</td>
</tr>
<tr class="child">
<td class="info">Sub Type</td>
<td>3,000</td>
</tr>
<tr class="parent">
<td class="info">Type</td>
<td>11,000</td>
</tr>
<tr class="child">
<td class="info">Sub Type</td>
<td>11,000</td>
</tr>
Now I would like to change the hash keys, by concatenating them with the text value in a td belonging to the parent tr. So in the above HTML structure, instead of "Sub Type" => 9000, "Sub Type" => 3000, etc. I would like to get "Type Sub Type" => 9000, "Type Sub Type" => 3000, etc.
How do I get the first preceding sibling with a certain class, when the number of siblings is unknown?

Answer 1

You can look at this a different way, loop through all tr elements (parent and child), keep the last found parent type and then concatenate the last parent type when you get to a child.
#counts = Hash.new
parent = nil
agent.page.search('.parent, .child').each do |node|
type = node.css('td')[0].text.strip
value = node.css('td')[1].text.gsub(/,/, '').to_i
if node['class'].include? 'parent'
parent = type
else
#counts["#{parent} #{type}"] = value
end
end
puts #counts.sort_by{|k,v| v}.reverse.to_h
Also, hashes are by nature an unsorted data structure. If you want to retain order, then your best bet would be an array of tuples. In other words, [['Type Sub Type', 12000], ['Type Sub Type', 11000], ..., ['Type Sub Type', 3000]]. Just remove the .t_h at the end of your last line to get that kind of result.