Edit form problem

I have this form <%= form_for @lesson do |f| %>           <%= f.label :lesson_name, "Lesson title" %></br>           <%= f.text_field :lesson_name, class: "form-control" %></br>           <%= f.label :lesson_icon, "Choise icon" %>           <%= f.select "lesson_icon", options_for_select([ "ico-03", "ico-04","ico-05","ico-06" ])%></br></br>           <div>             <p style="display:none"><%=hh=0%></p>            <%= f.fields_for :sublessons do |sublesson_a| %>

           <div class="delete-subtitle-<%=hh%>" style="padding-bottom: 25px;">               <%= sublesson_a.label :sublesson_name, "Subtitle 1" %></br>               <%= sublesson_a.text_field :sublesson_name, class: "form-control delete-sublesson-field-#{hh}" %></br>               <%= sublesson_a.label :sublesson_content, "Content" %></br>               <%=sublesson_a.text_area 'sublesson_content', rows: 3, class: "form-control delete-sublesson-content-#{hh}"%></br>               <%= sublesson_a.label :sublesson_video_link, "Video link" %><br>               <%= sublesson_a.text_field :sublesson_video_link, class: "form-control delete-sublesson-video-#{hh}" %></br>               <a style="float:right" class="btn btn-primary" id="remove_sublesson" onclick="remove_sublesson(<%=hh%>)">Delete Sublesson</a>               <p style="display:none"><%= hh=hh+1%></p>            </div>

          <%end%>          </div>

        <%= f.submit "Submit", class: "btn btn-primary" %>         <a class="btn btn-primary" id="addNewTag" onclick="add_sublesson()">Add Sublesson</a>

      <% end %>

This is a form for edit....How can i test if :sublessons is empty?

I suppose that your lesson ‘has_many’ sublessons. In this case you can check it as follows:

if @lesson.sublessons.any?

It returns true if the collection is not empty