Rails creating multidimensional array within loop - ruby-on-rails

Question

I'm trying to loop through an array of the next 7 days, and for each, perform a query to find all the 'Time slots' that match, and add these to an object which I can loop through in my view. This is fairly simple in PHP, but I'm not sure of the syntax in rails. I have a situation where each day can have multiple 'delivery slots' available, and I need to display all these slots for the next week, by day.
So far in my controller I have
d = Date.today
d2 = d + 1.week
#days = (d..d2).to_a
#deliveries = []
#days.each do |d|
#deliveries[][dayname] = d.strftime("%a")
#deliveries[][slots] = Model.where("day = ?", d.strftime("%w"))
end
Then in my view, I want to do this
<% #deliveries.each do |d| %>
<%= d.dayname %>
<% d.slots.each do |s| %>
<%= slot data here %>
<% end %>
<% end %>
Where am I going wrong? Not quite sure of the syntax in rails where you'd use "as key => value" in php. Is this the most efficient way to go about it? It will result in 7 queries which isn't ideal
Thanks for any help

Answer 1

If your Model only has a day number, the slots will be the same for every week and you could do something like:
slots_by_day = Model.all.group_by(&:day)
#deliveries = (Date.today..Date.today + 6.days).each_with_object({}) do |day, dayname_groups|
dayname_groups.merge!(day.strftime('%a') => slots_by_day[day.strftime('%w').to_i])
end
It will fetch all models, group them by day number of the week and then build a hash mapping each day number with the day name ending up in a hash like:
=> {"Wed"=>[#<Model...>, #<Model...>, #<Model...>, #<Model...>],
"Thu"=>[#<Model...>, #<Model...>, #<Model...>, #<Model...>], "Fri"=>...}
The hash would be used like this:
<% #deliveries.each do |dayname, slots| %>
<%= dayname %>
<% slots.each do |s| %>
<%= slot data here %>
<% end %>
<% end %>