Graph time-based data in irb

dotgraph.rb

#example data
data = [
  {
    :time => Time.now - 2.days,
    :value => 2321.65
  },
  {
    :time => Time.now - 1.days,
    :value => 1307.98
  },
  {
    :time => Time.now,
    :value => 2576
  }
]

#graph it. the maximum gets 100 dots
max = data.max_by{|a| a[:value]}[:value]
data.each do |a|
  puts (a[:time].to_formatted_s(:short) + ' ' + '%9.1f' % a[:value] + ' ' + '.'*(a[:value].to_f/max*100))
end

Grabbing data to graph:

data = []
(0..90).each do |i|
  data.push({
    :time => Time.now - (i+1).days,
    :value => ModelName.where(:created_at => (Time.now - (i+1).days)..(Time.now - i.days)).count
  })
end