In Rails, display time between two dates in English

Question

In a Rails project I want to find the difference between two dates and then display it in natural language. Something like

>> (date1 - date2).to_natur         


        

Answer 1

I tried Daniel's solution and found some incorrect results for a few test cases, due to the fact that it doesn't correctly handle the variable number of days found in months:

> 30.days < 1.month
   => false

So, for example:

> d1 = DateTime.civil(2011,4,4)
> d2 = d1 + 1.year + 5.months
> time_diff_in_natural_language(d1,d2)
=> "1 year, 5 months, 3 days" 

The following will give you the correct number of {years,months,days,hours,minutes,seconds}:

def time_diff(from_time, to_time)
  %w(year month day hour minute second).map do |interval|
    distance_in_seconds = (to_time.to_i - from_time.to_i).round(1)
    delta = (distance_in_seconds / 1.send(interval)).floor
    delta -= 1 if from_time + delta.send(interval) > to_time
    from_time += delta.send(interval)
    delta
  end
end
> time_diff(d1,d2)
 => [1, 5, 0, 0, 0, 0]