The Ruby Way: Solutions and Techniques in Ruby Programming, Second Edition

7.17. Computing the Difference in Two Date/Time Values

We can find the interval of time between two points in time. Subtracting one Time object from another gives us a number of seconds:

today = Time.local(2000,11,10)
yesterday = Time.local(2000,11,9)
diff = today - yesterday           # 86400 seconds

Once again, the function sec2dhms comes in handy. (This is defined in section 7.6 “Converting Between Seconds and Larger Units” earlier in the chapter.)

past = Time.local(1998,9,13,4,15)
now = Time.local(2000,11,10,22,42)
diff = now - past
unit = sec2dhms(diff)
puts "#{unit[0]} days,"            # 789 days,
puts "#{unit[1]} hours,"           # 18 hours,
puts "#{unit[2]} minutes,"         # 27 minutes,
puts "and #{unit[3]} seconds."     # and 0 seconds.