On Mon, Mar 2, 2009 at 10:50 AM, Ian Piper <[email protected]> wrote: > I am not sure > how best to manage the time measurements (DateTime or Time?) or how to > build the business rules to do the measurements and comparisons > robustly. > > I wondered whether anyone here could direct me to an example.
If you don't need increments smaller than 1 day, I prefer to use the Date class. I find it easier than Time to work with: * no ambiguity over "now" being a different date in different time zones etc * easier to compare date_1 == date_2 http://ruby-doc.org/stdlib/libdoc/date/rdoc/classes/Date.html A few simplistic examples: >> date = Date.today => Mon, 02 Mar 2009 >> next_month = date + 1.month => Thu, 02 Apr 2009 >> date = Date.new 2009,01,31 => Sat, 31 Jan 2009 >> next_month = date + 1.month => Sat, 28 Feb 2009 # automatic rounding down to valid date >> date = Date.new 2008,02,29 => Fri, 29 Feb 2008 >> next_year = date + 1.year => Sat, 28 Feb 2009 # automatic rounding down to valid date >> four_years_later = date + 4.year => Wed, 29 Feb 2012 Always be careful with comparing dates near the end of the months as months have a variable length. Easier comparison of date_1 == date_2 (compared to time_1 == time_2) >> date_1 = Date.today => Mon, 02 Mar 2009 >> date_2 = Date.today => Mon, 02 Mar 2009 >> date_1 == date_2 => true >> time_1 = Time.now => Mon Mar 02 11:24:59 +0100 2009 >> time_2 = Time.now => Mon Mar 02 11:25:06 +0100 2009 >> time_1 == time_2 => false HTH, Peter --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
