Rails creating multidimensional array within loop

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

akhanubis · Accepted Answer · 2013-09-11 12:31:05Z

2

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 %>

edited Sep 11, 2013 at 12:31

answered Sep 11, 2013 at 2:31

akhanubis

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3 Comments

Dave Over a year ago

Thanks so much, this looks perfect. But how would I pull the next 7 days in the correct order as I've done with the @days array above? I need to start on the current day, then pull the next 6

akhanubis Over a year ago

@Dave I edited my answer and it will give you a sorted hash as you need now

Dave Over a year ago

Perfect! Just needed to wrap the slots.each loop in a conditional <% if !slots.blank? %> - since not all days will have slots but I still want to dispaly them.

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