How to obtain first day of next month in ruby?

I have a date of operation. I want create promissory notes which have got:

day=1
month= the next month of operation_date
year= automatic

Example :

operation_date = 15/11/2010 
promissory_note1_date = 1/12/2010
promissory_note2_date = 1/01/2011
promissory_note3_date = 1/02/2011
promissory_note4_date = 1/02/2011

if exist four promissory notes

How could I make it?

PD: Excuse me my syntax

Solution 1:

You can do

require "active_support"

require "active_support/core_ext/date/calculations"
# || require "active_support/all"

Date.today.at_beginning_of_month
#=> Wed, 01 Dec 2010

Date.today.at_beginning_of_month.next_month
#=> Sat, 01 Jan 2011

Date.today.at_beginning_of_month.next_month.next_month
#=> Tue, 01 Feb 2011

And so on...

References

Rails guide 3.0 - 6.1.4 - ActiveSupport - How to Load Core Extensions
Rails guide 3.0 - 6.1.4 - ActiveSupport - Extensions to date

Solution 2:

In case you are not using rails or do not wish to require active_support, I found a simpler way without active_support

(Date.today - Date.today.mday + 1) # First day of the current month
=> Thu, 01 Dec 2016

Hope this helps! :-)

Solution 3:

A response to generically obtain N months (in rails)

(Date.today + N.months).at_beginning_of_month

Solution 4:

My solution:

class Time
  def start_of_next_month
    Time.local(self.year + self.month / 12, self.month % 12 + 1)
  end
end

Solution 5:

I am using Ruby 1.8.7 and 1.9.2 with rvm and in both cases Date.today results an error:

ruby-1.8.7-p302 > Date.today
NameError: uninitialized constant Date

ruby-1.9.2-p0 > Date.today
NameError: uninitialized constant Object::Date

I thing you should use Time.now and this link should help you http://pleac.sourceforge.net/pleac_ruby/datesandtimes.html .

I am not sure about availability of at_beginning_of_month method in ruby but it does exists in RoR.