# Operations with Time objects

Hi guys.
I want to know the time remain before an expiration.
If I do t_remained = Time.now - expiration I get a float object.
how can I convert it back to Time(days hours and minute)?

thanks

I have tried this:

t = Time.now
=> Thu Mar 13 12:57:47 +0100 2008

t1 = Time.now + 1.hours
=> Thu Mar 13 13:58:03 +0100 2008

t2 = t1 - t
=> 3615.968256

tot = Time.at(t2)
=> Thu Jan 01 02:00:15 +0100 1970

but I don’t know why the difference between t1 e t is 2 hours and not 1
hour?

Stefano Bortolotti wrote:

but I don’t know why the difference between t1 e t is 2 hours and not 1
hour?

a Time object doesn’t represent a duration (2 hours) it represents a
point in time (Jan 1st 1970, 2am). There’s no standard Ruby object
representing a time duration, but it seems that a Float (number of
seconds) is good enough.

you can always do (num_of_seconds / 1.hour) to give you a fractional
number of hours etc.

Gareth

On Mar 13, 2008, at 8:02 AM, Stefano Bortolotti wrote:

but I don’t know why the difference between t1 e t is 2 hours and
not 1
hour?

irb> t = Time.now
=> Thu Mar 13 09:26:37 -0400 2008
irb> t1 = Time.now + 3600
=> Thu Mar 13 10:26:56 -0400 2008
irb> t2 = t1 - t
=> 3618.385132
irb> Time.at(t2)
=> Wed Dec 31 20:00:18 -0500 1969

Because you’re not looking at the time zone (+0100).

-Rob

Thanks guys! I have done this:

def remaining_time
if expiration != nil
diff = expiration - Time.now

``````  days = (diff / 1.day).to_i
hours = ((diff / 1.hour) % 24).to_i
mins = ((diff / 1.minute) 60).to_i

if diff < 7.days
return days.to_s + "gg, " + hours.to_s + ":" + mins.to_s
else
return "more than 7 days"
end
end
``````

end

I’ll try to improve it! If you have some advices, they are wellcomes…

On Mar 13, 2008, at 12:11 PM, Stefano Bortolotti wrote:

`````` if diff < 7.days
return days.to_s + "gg, " + hours.to_s + ":" + mins.to_s
else
return "more than 7 days"
end
``````

end
end

I’ll try to improve it! If you have some advices, they are wellcomes…

Since you have 1.day, 1.hour, 1.min, I assume that you have
ActiveSupport and likely have Rails. In any case, you can use
distance_of_time_in_words

If you want to clean up your own method:

days, dayfrac = diff.divmod(1.day)
hours, hrfrac = dayfrac.divmod(1.hour)
mins, secs = hrfrac.divmod(1.min)

if days >= 7
return “more than 7 days”
else
result = []
result << “%sgg,”%days unless days.zero?
result << “%d:%0d”%[hours,mins]
return result.join(’ ')
end

-Rob

Rob B. wrote:

If you want to clean up your own method:

days, dayfrac = diff.divmod(1.day)
hours, hrfrac = dayfrac.divmod(1.hour)
mins, secs = hrfrac.divmod(1.min)

if days >= 7
return “more than 7 days”
else
result = []
result << “%sgg,”%days unless days.zero?
result << “%d:%0d”%[hours,mins]
return result.join(’ ')
end

-Rob

Thanks Rob, I knew about distance_of_time_in_words but I want my own
method.
Cool the divmod…

Rob B. wrote:

if days >= 7
return “more than 7 days”
else
result = []
result << “%sgg,”%days unless days.zero?
result << “%d:%0d”%[hours,mins]
return result.join(’ ')
end

Also, there is the duration gem :
http://wiki.rubyonrails.org/rails/pages/Duration .

Regards,

Siep