Array of Months Performance

array_of_months.rb

require 'benchmark/ips'

start_date = 1.year.ago.to_date
end_date = Date.today

Benchmark.ips do |x|
  x.report "map range with Date.new and strftime" do
    date_range = start_date..end_date
    date_months = date_range.map {|d| Date.new(d.year, d.month, 1) }.uniq
    date_months.map {|d| d.strftime "%d/%m/%Y" }
  end

  x.report "map range with beginning_of_month and to_s" do
    (start_date.to_date..end_date.to_date).map(&:beginning_of_month).uniq.map(&:to_s)
  end

  x.report "map range once with Date.new and strftime" do
    (start_date..end_date).map {|d| Date.new(d.year, d.month, 1).strftime "%d/%m/%Y" }.uniq
  end

  x.report "map range once with beginning_of_month and to_s" do
    (start_date.to_date..end_date.to_date).map {|d| d.beginning_of_month.to_s }.uniq
  end

  x.report "month increment loop" do
    dates = []
    date = start_date.beginning_of_month

    while date <= end_date.beginning_of_month do
      dates << date.to_date.to_s
      date += 1.month
    end

    dates
  end

  x.compare!
end


# Warming up --------------------------------------
# map range with Date.new and strftime
#                        201.000  i/100ms
# map range with beginning_of_month and to_s
#                        149.000  i/100ms
# map range once with Date.new and strftime
#                        184.000  i/100ms
# map range once with beginning_of_month and to_s
#                        147.000  i/100ms
# month increment loop     1.789k i/100ms
# Calculating -------------------------------------
# map range with Date.new and strftime
#                           2.140k (±17.5%) i/s -     10.452k in   5.027441s
# map range with beginning_of_month and to_s
#                           1.552k (±13.2%) i/s -      7.748k in   5.074306s
# map range once with Date.new and strftime
#                           1.823k (± 3.7%) i/s -      9.200k in   5.054044s
# map range once with beginning_of_month and to_s
#                           1.444k (± 6.9%) i/s -      7.203k in   5.011823s
# month increment loop     17.788k (± 5.1%) i/s -     89.450k in   5.042600s
#
# Comparison:
# month increment loop:    17788.3 i/s
# map range with Date.new and strftime:     2140.1 i/s - 8.31x  slower
# map range once with Date.new and strftime:     1822.6 i/s - 9.76x  slower
# map range with beginning_of_month and to_s:     1552.1 i/s - 11.46x  slower
# map range once with beginning_of_month and to_s:     1443.6 i/s - 12.32x  slower