build and iterate a sorted hash of items by class and sequence

gistfile1.rb

# build the classes hash
classes = Hash.new{|h, k| h[k] = []}
items.reject { |i| ! i[:class] }.each do |i|
    classes[i[:class]] << i
end

# iterate each class, then each sequence in that class
classes.keys.sort.each do |class, class_items|
    class_items.sort_by { |c| c[:sequence] }.each do |c|
        # 
    end
end