improve_code.rb

# app/models/vendor.rb
class Vendor < ActiveRecord::Base
  has_many :products

  # Rest of the code …
end

# app/models/product.rb
class Product < ActiveRecord::Base
  belongs_to :vendor
  has_many :taxes

  # Rest of the code …
end

# app/models/tax.rb
class Tax
  belongs_to :product
  
  # Rest of the code …
end


# Get the rates of the taxes applied to products prefixed by "Product 00" belonging the vendor with ID 41.

# vendor = Vendor.find 41
# items = Product.all.select { |item| item.account_id = vendor.id && item.description.match(/\AProduct\s00/) }
# ids = item.map(&:id)
# taxes = Tax.where(item_id: ids)
# rates = taxes.map(&:rate)

Tax.joins(products: :vendors)
   .where(products: {"description like ?", "Product 00%"}, vendors: {id: 41})
   .map(&:rate)