rails count records

Let say i have the following car loop and i want to display 4 cars on one row and then create a new row etc.

<table>
    <tr>
    <% @cars.each do |ca开发者_开发知识库r| %>
        <td><%= car.name %></td>
    <% end %>
    </tr>
</table>

So i looks like this:

car1 car2 car3 car4

car5 car6 car7 car8

car9 car10 ... ... ...

How do I do that?

<table>
  <% @cars.each_slice(4) do |cars| %>
    <tr>
      <% cars.each do |car| %>
        <td><%= car.name %></td>
      <% end %>
    </tr>
  <% end %>
</table>

Adding a class to last td in a row:

<table>
  <% @cars.each_slice(4) do |cars| %>
    <tr>
      <% cars.each do |car| %>
        <td <%= "class='my_class'" if car == cars.last %>>
          <%= car.name %>
        </td>
      <% end %>
    </tr>
  <% end %>
</table>

You can take advantage of the each_slice method from Enumerable, an example like so:

[1,2,3,4,5,6,7,8,9,10].each_slice(4).to_a
#=> [1, 2, 3, 4], [5, 6, 7, 8], [9, 10]] 

So your code would be like:

<table>
  <% @cars.each_slice(4) do |cars| %>
    <tr>
      <% cars.each do |c| %>
        <td><%= c.name %></td>
      <% end %>
    </tr>
  <% end %>
</table>

Point is, always check out the Enumerable page for things like this. Ruby provides amazing methods like this!