platipi

Array#in_groups_of, where have you been all of my life?

Today we were presented with the following problem in HAML:
We wanted several list items to be outputted in lists of 3.

Fairly simple in ERB, it would be something like this:

<% @activities.each do |a| %>
  <% if @i%3 == 0 >
    <ul>
  < end >
  <li><%= link_to a.name, a %>
  <% if @i%3 == 0 >
    </ul>
  < end >
  <% @i += 1 >

However, HAML would prove to be a problem due to indentations.
Consider the following code:

-@activities.each do |a|
  -if @i%3 == 0
    %ul
  %li=link_to a.name, a
  -@i += 1

This won't work, since our %li would be outside of our %ul. We can't put it inside without having either incorrect nesting or HAML indentation errors.

We asked help from stackoverflow (gotta love this site) and someone proposed using Array#in_groups_of:

-@activities.in_groups_of(3, false) do |activity_group|
  %ul
    -activity_group.each do |activity|
    %li=link_to activity.name, activity

Worked like magic. in_groups_of saved the day.

More information can be found on Railscast.