Question

In Ruby on Rails, how can I access the iteration counter within a loop?

The following works, but using the child_number variable is a bit of a hack. Is there a better way of achieving this?

<% 5.times { @parent.child.build } %>

<%= form_for @parent do |parent_form| %>
  <p>
    <%= parent_form.label :full_name, "Parent's name" %>
    <%= parent_form.text_field :full_name %>
  </p>

  <%= parent_form.fields_for :children do |child_form| %>
    <% @child_number ||= 1 %>
    <p>
      <%= child_form.label :full_name, "Child #{@child_number}'s name" %>
      <%= child_form.text_field :full_name %>
    </p>
    <% @child_number += 1 %>
  <% end %>

  <p>
    <%= parent_form.submit %>
  </p>
<% end %>

Answer 1

Well, it’ll be in the Rails 3.2 – https://github.com/rails/rails/pull/1189

…I will assign it to 3.2 milestone…

It’ll be look like https://github.com/jmbejar/rails/commit/7c562d5e460d97b18e4f3367b3cfb13401732920

Now you can use something like that:

<% 5.times { @parent.child.build } %>

<%= form_for @parent do |parent_form| %>
  ...
  <%= parent_form.fields_for :children do |child_form| %>
    <p>
      <%= child_form.label :full_name, "Child #{child_form.object_name.gsub(/[^0-9]+/,'')}'s name" %>
      <%= child_form.text_field :full_name %>
    </p>
  <% end %>
  ...
<% end %>