Create a graph accumulating data over time - ruby on rails

Question

I want to create a graph, for example "number of accumulative likes over time" in ruby on rails. I need to do something like get the base likes:

base_likes = Like.find :all, :conditions => ["created_at < ?", from_date]

And get the number of likes per day in array:

[3, 0, 10, 12, 0, 24]

And then loop through the number likes per day including the base likes to get an array like:

[3, 3, 13, 25, 25, 49]

I wondered if there was a magic ruby way?!

Thanks, A

Answer 1

To retrieve information from the db, I'd head first to:

hash = Like.count(:group => "date(created_at)")

But this will provide only days where here have been likes so it could be a pain to fill in the gaps.

Otherwise, looking here, you could create your array of likes per day.

Then to get the cumulative likes, I'd do:

ary = [3, 0, 10, 12, 0, 24]
ary.each_with_index.map {|e,i| ary[0..i].inject(&:+)}