红宝石计算表值总计

Question

How can the total of a variable I define be calculated?

I have:

product_sale.rb

def totalprice
  price*quantity
end

view

%h1 Listing Product Sales
%table
  %thead
    %tr
      %th Product name
      %th Price
      %th Quantity
      %th Total price
  %tbody
    - @product_sales.each do |product_sale|
      %tr
        %td= product_sale.product_name
        %td= product_sale.price
        %td= product_sale.quantity
        %td= product_sale.totalprice
%br
%h1
  Total sum to be paid:
  = Product_sale.sum(:totalprice)

the = Product_sale.sum(:totalprice) does not work. How can I calculate it?

Answer 1

@product_sales.map(&:totalprice).sum

Answer 2

@product_sales.sum('price * quantity') # single query, efficient

PS该类的正确名称是蛇形ProductSale

Answer 3

@product_sales.sum(&:totalprice)

我认为这应该适用于您只汇总所选产品销售总价的情况

Answer 4

@product_sales.sum('price * quantity')

Answer 5

Best solution for me was the one of Max:

controller index view: @some_total = @product_sales.map(&:totalprice).sum

view: = @some_total