Rails数量奇异地添加（将运费总计）

Question

I have a store set up on my app and in one stage of the checkout process it has to add the shipping rate to the subtotal to get the total (should be simple). However, when the shipping rate is a single digit (eg ($2.00)) it adds correctly like this:

$32 subtotal + $6 shipping = $38 total

HOWEVER, when the shipping rate is a double digit it adds like this:

$32 subtotal + $23 shipping = $34 total

From what I can tell it must be something hinky with the place values, but I can't figure out what it is, leading me to believe there's some idiosyncratic Ruby thing I'm doing wrong.

On my ERB view, here is how the form looks:

  <% shipping_choices = [] %>
    <% @usps_rates.each do |rate| %>
      <% choice = [] %>
      <% choice << [rate[1], rate[0]] %> <!-- value ( $, desc ) -->
      <% choice << number_to_currency(rate[1]/100, precision: 2).to_s + " - " + rate[0].to_s %> <!-- description -->
      <% shipping_choices << choice %>
    <% end %>
    <%= simple_form_for @order, url: charges_update_order_path(:shipping), method: :post do |f| %>
      <div class="row">
        <div class="form-inputs text-left">
          <div class="form-group">
            <%= f.collection_radio_buttons :shipping, shipping_choices, :first, :last, item_wrapper_class: :block_radio_button_collection %>
          </div>
        </div> <!-- form inputs -->
      </div> <!-- choices row -->
      <div class="row">
        <%= f.button :submit, "Continue to Billing", class: "btn btn-manly" %>
      </div>
    <% end %>

And this is the order model where the information is being saved:

def update_order_from_shipping_page(shipping_pair)
  self.shipping = shipping_pair[0]
  self.shipping_choice = shipping_pair[1]
  new_total = self.subtotal + self.shipping
  self.update_attributes(total: new_total, shipping_choice: self.shipping_choice)
end

Can anyone see where things are going wrong?

Answer 1

It turned out that this line:

number_to_currency(rate[1]/100, precision: 2).to_s

Needed parentheses around it like this:

(number_to_currency(rate[1]/100, precision: 2)).to_s

For some reason that did the trick.