hash最小值过滤算法

[["数量","包装","价格"],["数量","包装","价格"],["数量","包装","价格"]]

要求取出相同包装数量的最低价格结果集

例子：[[10,"kg",200],[10,"kg",300],[20,"kg",100],[20,"kg",200],[30,"kg",200]]

results = [[10,"kg",200],[10,"kg",300],[20,"kg",100],[20,"kg",200],[30,"kg",200]]
result_hash = {}
results.each do |result|
     result_hash[result[0]] = result unless result_hash[package_unit].present? && result_hash[result[0]][0] > result[0]
end
results = result_hash.values

StockChemicalPrice 模型下有一个字断记录报价方案：
{levels: "5,10,100", prices: "100,200,300", fees: "0,0,10"}
解析报价方案，取同包装最低报价方案

def get_stock_hash(source_entity_type)
    return_result = []
    purity_stock  = StockChemicalPrice.standard_package.where(active: 1, stock_chemical_id: self.id, source_entity_type: source_entity_type).group_by(&:purity)
    purity_stock.each do |purity,stocks|
      stocks.group_by(&:package_unit).each do |package_unit,stock|
        results = []
        stock.each do |data|
          purity = purity
          package_unit = package_unit
          package_unit_int = data.package_unit_before_type_cast
          stock_id = data.id
          levels = data.hash_rules[:levels].split(',')
          prices = data.hash_rules[:prices].split(',')
          levels.each_with_index do |l,i|
            results << [stock_id,"#{l}#{package_unit}",purity,package_unit,prices[i],l,package_unit_int]
          end
          if levels.uniq != levels
            result_hash = {}
            results.each do |result|
              result_hash[result[4]] = result unless result_hash[package_unit].present? && result_hash[result[4]][4] > result[4]
            end
            results = result_hash.values
          end
        end
        return_result += results
      end
    end
    return return_result
  end