More precise distance_of_time_in_words

Question

distance_of_time_in_words is great, but sometimes it's not granular enough.

I need a function that will report exact distances of time in words. E.g., 7:50AM to 10:10AM should be a distance of "2 hours and 20 minutes", not "about 2 hours" or whatever distance_of_time_in_words would do.

My use case is reporting train schedules, and in particular how long a given train ride will take.

Answer 1

def distance_of_time_in_hours_and_minutes(from_time, to_time)
  from_time = from_time.to_time if from_time.respond_to?(:to_time)
  to_time = to_time.to_time if to_time.respond_to?(:to_time)
  distance_in_hours   = (((to_time - from_time).abs) / 3600).round
  distance_in_minutes = ((((to_time - from_time).abs) % 3600) / 60).round

  difference_in_words = ''

  difference_in_words << "#{distance_in_hours} #{distance_in_hours > 1 ? 'hours' : 'hour' } and " if distance_in_hours > 0
  difference_in_words << "#{distance_in_minutes} #{distance_in_minutes == 1 ? 'minute' : 'minutes' }"
end

Answer 2

https://github.com/radar/dotiw/tree works even better, actually.

Answer 3

The above code confused my Rubymine ... and I'm not sure it's actually correct. I rebuilt it as follows:

def distance_of_time_in_hours_and_minutes(from_time, to_time)
  from_time = from_time.to_time if from_time.respond_to?(:to_time)
  to_time = to_time.to_time if to_time.respond_to?(:to_time)
  dist = to_time - from_time
  minutes = (dist.abs / 60).round
  hours = minutes / 60
  minutes = minutes - (hours * 60)

  words = dist <= 0 ? '' : '-'

  words << "#{hours} #{hours > 1 ? 'hours' : 'hour' } and " if hours > 0
  words << "#{minutes} #{minutes == 1 ? 'minute' : 'minutes' }"
end

Here's some Rspec for the above:

describe "Distance of Time in Hours and Minutes" do
  before do
    @time1 = Time.utc(2010,"sep",7,14,15,3)
    @time2 = @time1 + 28
    @time3 = @time1 + 30
    @time4 = @time1 + 60
    @time5 = @time1 + 60*60
    @time6 = @time1 + 60*60 + 60
    @time7 = @time1 + 60*60 + 5*60
  end

  it "calculates time differences properly" do
    distance_of_time_in_hours_and_minutes(@time1, @time1).should == "0 minutes"
    distance_of_time_in_hours_and_minutes(@time1, @time2).should == "0 minutes"
    distance_of_time_in_hours_and_minutes(@time1, @time3).should == "1 minute"
    distance_of_time_in_hours_and_minutes(@time1, @time4).should == "1 minute"
    distance_of_time_in_hours_and_minutes(@time1, @time5).should == "1 hour and 0 minutes"
    distance_of_time_in_hours_and_minutes(@time1, @time6).should == "1 hour and 1 minute"
    distance_of_time_in_hours_and_minutes(@time1, @time7).should == "1 hour and 5 minutes"
    distance_of_time_in_hours_and_minutes(@time7, @time1).should == "-1 hour and 5 minutes"
    distance_of_time_in_hours_and_minutes(@time3, @time1).should == "-1 minute"
  end
end

(Note that I had prepend each invocation of distance_of_time_in_miles with helper in my coding environment to avoid a NoMethodError error -- see for instance http://old.nabble.com/How-to-spec-a-Rails-helper-method-td20660744.html for more on that.