accessing object attributes

I have an hash of display names and their corresponding object
attribute names called @columns.
As I iterate through @columns, what is the syntax for accessing the
attribute of the object using c? I get an error on the 4th line.

        <% for c in @columns["object_"+@object.categorie] do %>
           <tr>
           <td class="name"><%=c.first%></td>
           <td><%= @object.c.second %></td>
           </tr>

        <% end %>

It's really hard for me to tell what you're trying to do here. How about
we simplify and take it from there?

<% @columns.each do |key, value| %>
  <%= key %> = <% value %>
<% end %>

Now, what is "@object" and how does it relate to the contents of
either 'key' or 'value'?

Thanks for your reply!
I have figured it out...

it should be

           <td><%= @echantillon[c.second] %></td>