Question

I would like to sort through a table (Lessons) and group them by Subject(A field in the Lesson’s table). Then display them by subject.

So I would have a header: Subject

Then it would display the image, title and description for each item in that subject.
Then it would move onto the next Subject and so on up to 5 items

For example:

Math
[img]   [img]   [img]  ...
title   title   title  ...
desc    desc    desc   ...

Science
[img]   [img]   [img]  ...
title   title   title  ...
desc    desc    desc   ...

etc.....

In the controller how would you go about sorting and then dividing up?

How do you display this in the view if you have a dynamic amount of subjects?

Answer 1

The meat of your needs are met by Enumerable#group_by:

my_lessons.sort_by{ |lesson|
  # Or use ActiveRecord to sort your data
  lesson.title
}.group_by{ |lesson|
  lesson.subject
}.each do |subject,subj_lessons|
  puts "subject: #{subject}"
  subj_lessons.each do |lesson|
    puts lesson.title
  end
end

Whatever you return from group_by will be the key for your hash, while the value (subj_lessons) is an array of all the items that matched that grouping.

Modify this to fit your actual data and your output needs.