# Time Diff Module **URL:** \ **Category:** Ruby\ **Created:** [January 17, 2006, 6:25pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654 "2006-01-17T18:25:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![crucoba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@crucoba](https://www.ruby-forum.com/u/crucoba)\ **Post date:** [January 17, 2006, 6:25pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654/1 "2006-01-17T18:25:23Z")
Anyone know of a module out there that will encapsulate differences in time? Ideally I would want something like this: d1 = DateTime.now + 2.hours + 2.minutes d2 = DateTime.now diff = d1-d2 puts “Diff: #{diff.hours}:#{diff.minutes}” > > Diff: 2:02 I have searched for examples and all of them seem to be doing this manually. Dave ---
**Author:** ![crucoba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@crucoba](https://www.ruby-forum.com/u/crucoba)\ **Post date:** [January 17, 2006, 6:37pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654/2 "2006-01-17T18:37:26Z")
On 1/17/06, David C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > puts “Diff: #{diff.hours}:#{diff.minutes}” > > > > Diff: 2:02 > > I have searched for examples and all of them seem to be doing this manually. > > Dave Runt may have what you’re looking for: [http://runt.rubyforge.org/](http://runt.rubyforge.org/) Tutorial: [http://runt.rubyforge.org/doc/files/doc/tutorial\_te\_rdoc.html](http://runt.rubyforge.org/doc/files/doc/tutorial_te_rdoc.html) ---
**Author:** ![crucoba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@crucoba](https://www.ruby-forum.com/u/crucoba)\ **Post date:** [January 17, 2006, 6:40pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654/3 "2006-01-17T18:40:27Z")
On Wed, 2006-01-18 at 01:48 +0900, David C. wrote: > puts “Diff: #{diff.hours}:#{diff.minutes}” > > > > Diff: 2:02 > > I have searched for examples and all of them seem to be doing this manually. > > Dave Ruby on Rails’ ActiveSupport::CoreExtensions::Numeric::Time module supports this. The gem is activesupport. You might want to extract it somehow to avoid getting the rest of the library if you don’t need it. Jon ---
**Author:** ![crucoba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@crucoba](https://www.ruby-forum.com/u/crucoba)\ **Post date:** [March 9, 2011, 5:02pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654/4 "2011-03-09T17:02:57Z")
David C. wrote in post #23880: > Anyone know of a module out there that will encapsulate differences in > time? > > Ideally I would want something like this: > > d1 = DateTime.now + 2.hours + 2.minutes > d2 = DateTime.now > > diff = d1-d2 > > puts “Diff: #{diff.hours}:#{diff.minutes}” > > > > Diff: 2:02 > > I have searched for examples and all of them seem to be doing this > manually. > > Dave There is a gem available to find the difference in a useful way. [https://rubygems.org/gems/time\_diff](https://rubygems.org/gems/time_diff) This will return a hash of difference in year, month, week, day, hour, minute, second ---
**Author:** ![crucoba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@crucoba](https://www.ruby-forum.com/u/crucoba)\ **Post date:** [January 17, 2006, 11:05pm UTC](https://www.ruby-forum.com/t/time-diff-module/52654/5 "2006-01-17T23:05:52Z")
On Wed, 18 Jan 2006, David C. wrote: > puts “Diff: #{diff.hours}:#{diff.minutes}” > > > > Diff: 2:02 > > I have searched for examples and all of them seem to be doing this manually. i’m guessing the reason this has not been done generically is that it is incredibly slippery. for instance, if i had a = DateTime::new 1582, 8, 4 b = a + 1.day then b should the the day ‘1582-08-15’. and diff = b - a p diff.days should output either 10 or 1 - depending on how you look at it. the reason is the fact that DateTime makes all the calender reforms between julian and gregorian transparent and even handles them based on timezone. not saying it could not be done, but it’s tough and, afaik, hasn’t been. see ruby-1.8.4/lib/date.rb for details. of course, activesupport give you Numeric#days, etc, but that is quite easy to roll. if the code you posted is pretty close you what you actually need then why not simply use Time objects, converting to DateTime as needed using DateTime::new(t.year, t.month, t.day… etc)? ``` harp:~ > cat a.rb class Time module Units def __less__ () "/" end def __more__ () "*" end def milliseconds() self.send( __less__ ,1000) end; alias_method ``` “millisecond”, “milliseconds” def seconds() self end; alias\_method “second”, “seconds” def minutes() seconds.send( **more** ,60) end; alias\_method “minute”, “minutes” def hours() minutes.send( **more** ,60) end; alias\_method “hour”, “hours” def days() hours.send( **more** ,24) end; alias\_method “day”, “days” def weeks() days.send( **more** ,7) end; alias\_method “week”, “weeks” def months() weeks.send( **more** ,4) end; alias\_method “month”, “months” def years() months.send( **more** ,12) end; alias\_method “year”, “years” def decades() years.send( **more** ,10) end; alias\_method “decade”, “decades” def centuries() decades.send( **more** ,10) end; alias\_method “century”, “centuries” end module DiffUnits include ::Time::Units def **less** () “\*” end def **more** () “/” end end alias\_method “ **delta** ”, “-” def - other ret = **delta** other ret.extend DiffUnits ret end end class Numeric include ::Time::Units end ``` now = Time::now a = now b = now + 2.hours + 2.minutes d = b - a require "yaml" %w( seconds minutes hours days ).each{|m| y m => d.send(m)} harp:~ > ruby a.rb --- seconds: 7320.0 --- minutes: 122.0 --- hours: 2.03333333333333 --- days: 0.0847222222222222 ``` hmmm. maybe i’ll add this to alib… cheers. -a