Question

How do you convert between a DateTime and a Time object in Ruby?

Answer 1

You’ll need two slightly different conversions.

To convert from Time to DateTime you can amend the Time class as follows:

require 'date' class Time   def to_datetime     # Convert seconds + microseconds into a fractional number of seconds     seconds = sec + Rational(usec, 10**6)      # Convert a UTC offset measured in minutes to one measured in a     # fraction of a day.     offset = Rational(utc_offset, 60 * 60 * 24)     DateTime.new(year, month, day, hour, min, seconds, offset)   end end 

Similar adjustments to Date will let you convert DateTime to Time .

class Date   def to_gm_time     to_time(new_offset, :gm)   end    def to_local_time     to_time(new_offset(DateTime.now.offset-offset), :local)   end    private   def to_time(dest, method)     #Convert a fraction of a day to a number of microseconds     usec = (dest.sec_fraction * 60 * 60 * 24 * (10**6)).to_i     Time.send(method, dest.year, dest.month, dest.day, dest.hour, dest.min,               dest.sec, usec)   end end 

Note that you have to choose between local time and GM/UTC time.

Both the above code snippets are taken from O’Reilly’s Ruby Cookbook. Their code reuse policy permits this.