cycle(first_value, *values) public

Creates a Cycle object whose to_s method cycles through elements of an array every time it is called. This can be used for example, to alternate classes for table rows: 

  <% @items.each do |item| %>
    <tr class="<%= cycle("even", "odd") -%>">
      <td>item</td>
    </tr>
  <% end %>

You can use named cycles to allow nesting in loops. Passing a Hash as the last parameter with a :name key will create a named cycle. You can manually reset a cycle by calling reset_cycle and passing the name of the cycle. 

  <% @items.each do |item| %>
    <tr class="<%= cycle("even", "odd", :name => "row_class")
      <td>
        <% item.values.each do |value| %>
          <span style="color:<%= cycle("red", "green", "blue", :name => "colors") -%>">
            value
          </span>
        <% end %>
        <% reset_cycle("colors") %>
      </td>
   </tr>
 <% end %>
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April 20, 2009
2 thanks

Cycle with first and last

I needed a cycle that was also aware of the first and last items in the collection. This is adapted from a snippet I found while Googling:

def cycle_with_first_last(object, collection, options = { })
  addition = ""
  addition += " #{options[:first]}" if object == collection.first
  addition += " #{options[:last]}"if object == collection.last
  cycle(options[:odd], options[:even]) + addition
end

Just put that in your helpers…

September 11, 2008
1 thank

CSS columns

You can also use this in a partial to create blocks of content into columns without setting a fixed height. This one is two columns.

.clear { clear: both;}
.block { float:left;width:200px;}

<div class="block">

<p>Content Item</p>

</div>
<%= cycle("", "<div class=\"clear\"></div>") -%>