CODEWITHSUNDEEP
rubyruby-on-rails-4
sm83
sm83

Reputation: 15

How do I add variable number of months to a date in Ruby (avoid using loop)

Is there something similar to the code below in Ruby where X stands for the number of months to add to today's date but is coming from a variable

Time.zone.today + X.month ## X comes from a variable

Preferably without using a loop as 'm' can be large number in the example below

def add_months_to_today(m)
  number_of_months_to_add = m.to_i
  return_date = Time.zone.today
  if m.to_i > 0
    (1..number_of_months_to_add).each do |i|
      return_date = return_date + 1.month
    end     
  end

  return_date
end

Upvotes: 1

Views: 522

Answers (1)

Stefan
Stefan

Reputation: 114248

Your code works perfectly fine:

x = 4
Time.zone.today + x.month
#=> Sun, 29 Sep 2019

month is a method defined on Integer. It doesn't matter if the integer is given as a literal or as a variable. The receiver just has to be an Integer.

Instead of Time.zone.today you could also call Date.current:

Date.current + 4.month  #=> Sun, 29 Sep 2019

Rails also adds a variety of other methods to Date: (also via DateAndTime::Calculations)

Date.current.advance(months: 4) #=> Sun, 29 Sep 2019
Date.current.months_since(4)    #=> Sun, 29 Sep 2019
4.months.since(Date.current)    #=> Sun, 29 Sep 2019

The above also work for instances of Time:

Time.current.advance(months: 4) #=> Sun, 29 Sep 2019 10:11:52 CEST +02:00
Time.current.months_since(4)    #=> Sun, 29 Sep 2019 10:11:52 CEST +02:00
4.months.since                  #=> Sun, 29 Sep 2019 10:11:52 CEST +02:00

When only dealing with dates, Ruby's built-in >> or next_month might be used as well:

Date.current >> 4
#=> Sun, 29 Sep 2019

Date.current.next_month(4)
#=> Sun, 29 Sep 2019

Note that you can use 4 and x interchangeably in all of the above examples.

Upvotes: 4

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