Ruby - Calculate time duration into percentages of a whole month

I want to calculate the duration of time from a specific start and end time and output it in hours/minuts/seconds and how long that duration is compared to the whole month in percent.

Sometimes the total duration during a month is 开发者_运维百科in multiple duration blocks. Here is an example:

Thinking out load with Ruby:

Start = Date.new(2011-09-01 00:00:00)  #24h clock - start of month
End = Date.new(2011-09-31 24:00:00) # end of month
Duration1 = Date.new(2011-09-03 12:30:00) Date.new(2011-09-11 12:30:00) #From - to
Duration2 = Date.new(2011-09-13 12:30:00) Date.new(2011-09-18 12:30:00) #From - to

Duration = Duration 1 + Duration2 #Might be even more durations during a month

Puts Duration.to_s
Total = Start + End
Percentage = (Duration / Total) * 100

Any idea how I could create a method out of the above code? It would be awesome if I could run something like or something even simpler:

Duration1 = Timedifference "2011-09-03 12:30:00", "2011-09-11 12:30:00" # Specify duration like this
Duration2 = Timedifference "2011-09-13 12:30:00", "2011-09-18 12:30:00" # Specify duration like this
Duration = Duration1 + Duration2
puts Duration
puts Percentage.Duration

Thanks in advance for your help.

---

There are quite a few ways to go about solving this problem. Assuming one wants to avoid dependencies on anything but the standard libraries, this is how I would do it:

require 'time'

# Calculate difference between two given Time objects
# and output as hours, minutes and seconds
def duration(time_start, time_end)
  secs  = (time_end - time_start).to_i
  hours = secs / 3600;
  secs -= hours * 3600
  mins  = secs / 60;
  secs -= mins * 60
  puts "#{hours}h #{mins}m #{secs}s"
end

# EDIT: Simpler and more elegant method (thanks to @knut)
def duration2(time_start, time_end)
  puts Time.at(time_end - time_start).gmtime.strftime('%dd %Hh %Mm %Ss')
end

# Calculate the difference between two given Time objects,
# and the duration of the month the latter is in, then
# output the ratio as a percentage with 2 decimal places
def percentage_of_month(time_start, time_end)
  time_secs  = time_end - time_start
  month_this = Date.civil(time_end.year, time_end.month, 1)
  month_next = month_this.next_month
  month_secs = (month_next - month_this) * 24 * 3600
  percentage = (time_secs * 100.0 / month_secs)
  puts '%2.2f%%' % percentage
end

time1a = Time.parse '2011-09-03 12:30:00'
time1b = Time.parse '2011-09-11 12:30:00'
duration time1a, time1b             # => 192h 0m 0s
percentage_of_month time1a, time1b  # => 26.67%

time2a = Time.parse '2011-09-13 12:30:00'
time2b = Time.parse '2011-09-18 12:30:00'
duration time2a, time2b             # => 120h 0m 0s
percentage_of_month time2a, time2b  # => 16.67%

time3a = Time.parse '2011-08-30 11:03:18'
time3b = Time.parse '2011-08-30 23:31:54'
duration time3a, time3b             # => 12h 28m 36s
percentage_of_month time3a, time3b  # => 1.68%

---

The output in hours/minuts/seconds is quite easy:

Time.at(duration).gmtime.strftime("%R:%S")

Details see http://www.ruby-forum.com/topic/48877

For the percentage I would need a more detailed specification.

• What's the base of your month? February has 28 days (but do not forget leap years), other months have 30 or 31 days.
• May your durations span different months?
• Could you give some test data and your expected result?

Below one solution with some assumptions.

require 'date'

=begin rdoc
Calculate seconds for a given month
=end
def seconds_of_month( year, month )  
  raise ArgumentError if month > 12
  month_start = DateTime.new(year, month, 1, 0)  #24h clock ,  start of month
  if month == 12
    month_end = DateTime.new(year + 1, 1, 1, 0) # jan 1st of following year
  else
    month_end = DateTime.new(year, month+1, 1) # start of next month
  end
  days = month_end -  month_start 
  #~ puts "%i-%i has %i days (%s-%s)" % [year, month, days, month_start, month_end ]
  days * 24 * 60 * 60 #convert month in second --- no check for leap seconds
end

=begin rdoc
Calculate percentage of duration in seconds per month.
=end
def percentage_of_month( duration, year, month )
  (duration / seconds_of_month(year,month)) * 100
end


duration = #=> 1123200s
  ( Time.local(2011, 9, 11, 12, 30, 00) - Time.local(2011, 9, 03, 12, 30, 00) ) +
  ( Time.local(2011, 9, 18, 12, 30, 00) - Time.local(2011, 9, 13, 12, 30, 00) )


1.upto(12){|mon|
  puts '%is is %.2f%% of 2011/%i (%is)' % [ duration, percentage_of_month( duration, 2011,mon), mon, seconds_of_month( 2011, mon )   ]
}

Result:

1123200s is 41.94% of 2011/1 (2678400s)
1123200s is 46.43% of 2011/2 (2419200s)
1123200s is 41.94% of 2011/3 (2678400s)
1123200s is 43.33% of 2011/4 (2592000s)
1123200s is 41.94% of 2011/5 (2678400s)
1123200s is 43.33% of 2011/6 (2592000s)
1123200s is 41.94% of 2011/7 (2678400s)
1123200s is 41.94% of 2011/8 (2678400s)
1123200s is 43.33% of 2011/9 (2592000s)
1123200s is 41.94% of 2011/10 (2678400s)
1123200s is 43.33% of 2011/11 (2592000s)
1123200s is 41.94% of 2011/12 (2678400s)

---

Or the very easy version:

days_in_month = Date.today.end_of_month.day.to_f    
day_of_month = Date.today.strftime('%-d').to_f    
percentage_of_way_through_month = day_of_month/days_in_month    

or the reverse if you need remainder of the month:

days_in_month = Date.today.end_of_month.day.to_f    
day_of_month = Date.today.strftime('%-d').to_f    
percentage_of_month_to_go = 1-(day_of_month/days_in_month)