Benchmarking creating arrays of time ranges, using Range and a while loop.

time_ranges.rb

require 'benchmark'
require 'time'

SECS_IN_HOUR = 3600

def while_loop
  now = Time.now
  ago = now - (SECS_IN_HOUR * 23)
  max, count, times = now.to_i, ago.to_i, []
  begin
    times << Time.at(count)
  end while (count += SECS_IN_HOUR) <= max
  times
end

def range
  now = Time.now
  ago = now - (SECS_IN_HOUR * 23)
  (ago.to_i..now.to_i).step(SECS_IN_HOUR).map { |s| Time.at(s) }
end

Benchmark.bmbm do |x|
  x.report('while_loop') do
    500_000.times { while_loop }
  end

  x.report('range') do
    500_000.times { range }
  end
end

# Rehearsal ----------------------------------------------
# while_loop   7.560000   0.770000   8.330000 (  8.429125)
# range        9.460000   0.570000  10.030000 ( 10.616442)
# ------------------------------------ total: 18.360000sec
# 
#                  user     system      total        real
# while_loop   7.490000   0.530000   8.020000 (  8.134457)
# range        9.340000   0.510000   9.850000 (  9.955324)