[ruby] Count number of days between two dates

How do I count the number of days between these two dates?

start_date = Date.parse "2012-03-02 14:46:21 +0100"
end_date =  Date.parse "2012-04-02 14:46:21 +0200"

to get the number of days in a time range (just a count of all days)

(start_date..end_date).count
(start_date..end_date).to_a.size
#=> 32

to get the number of days between 2 dates

(start_date...end_date).count
(start_date...end_date).to_a.size
#=> 31

I kept getting results in seconds, so this worked for me:

(Time.now - self.created_at) / 86400

To get the number of days difference by two dates:

(start.to_date...end.to_date).count - 1
or 
(end.to_date - start.to_date).to_i

None of the previous answers (to this date) gives the correct difference in days between two dates.

The one that comes closest is by thatdankent. A full answer would convert to_i and then divide:

(Time.now.to_i - 23.hours.ago.to_i) / 86400
>> 0

(Time.now.to_i - 25.hours.ago.to_i) / 86400
>> 1

(Time.now.to_i - 1.day.ago.to_i) / 86400
>> 1

In the question's specific example, one should not parse to Date if the time passed is relevant. Use Time.parse instead.

def business_days_between(date1, date2)
  business_days = 0
  date = date2
  while date > date1
   business_days = business_days + 1 unless date.saturday? or date.sunday?
   date = date - 1.day
  end
  business_days
end

Assuming that end_date and start_date are both of class ActiveSupport::TimeWithZone in Rails, then you can use:

(end_date.to_date - start_date.to_date).to_i

(end_date - start_date)/1000/60/60/24

any one have best practice please comment below

Rails has some built in helpers that might solve this for you. One thing to keep in mind is that this is part of the Actionview Helpers, so they wont be available directly from the console.

Try this

<% start_time =  "2012-03-02 14:46:21 +0100" %>
<% end_time   =  "2012-04-02 14:46:21 +0200" %>
<%= distance_of_time_in_words(start_time, end_time)  %>

 "about 1 month"

To have the number of whole days between two dates (DateTime objects):

((end_at - start_at).to_f / 1.day).floor

Very late, but it may help others:

end_date.mjd - start_date.mjd

https://apidock.com/ruby/Date/mjd