Get last day of the month in Ruby

Question

I made new object Date.new with args (year, month). After create ruby added 01 number of day to this object by default. Is there any way to add not first day, but last day o

Answer 1

So I was searching in Google for the same thing here...

I wasn't happy with above so my solution after reading documentation in RUBY-DOC was:

Example to get 10/31/2014

Date.new(2014,10,1).next_month.prev_day

Answer 2

To get the end of the month you can also use ActiveSupport's helper end_of_month.

# Require extensions explicitly if you are not in a Rails environment
require 'active_support/core_ext' 

p Time.now.utc.end_of_month # => 2013-01-31 23:59:59 UTC
p Date.today.end_of_month   # => Thu, 31 Jan 2013

You can find out more on end_of_month in the Rails API Docs.

Answer 3

require "date"
def find_last_day_of_month(_date)
 if(_date.instance_of? String)
   @end_of_the_month = Date.parse(_date.next_month.strftime("%Y-%m-01")) - 1
 else if(_date.instance_of? Date)
   @end_of_the_month = _date.next_month.strftime("%Y-%m-01") - 1
 end
 return @end_of_the_month
end

find_last_day_of_month("2018-01-01")

This is another way to find

Answer 4

This is my Time based solution. I have a personal preference to it compared to Date although the Date solutions proposed above read somehow better.

reference_time ||= Time.now
return (Time.new(reference_time.year, (reference_time.month % 12) + 1) - 1).day

btw for December you can see that year is not flipped. But this is irrelevant for the question because december always has 31 day. And for February year does not need flipping. So if you have another use case that needs year to be correct, then make sure to also change year.

Answer 5

use Date.civil

With Date.civil(y, m, d) or its alias .new(y, m, d), you can create a new Date object. The values for day (d) and month (m) can be negative in which case they count backwards from the end of the year and the end of the month respectively.

=> Date.civil(2010, 02, -1)
=> Sun, 28 Feb 2010
>> Date.civil(2010, -1, -5)
=> Mon, 27 Dec 2010

Answer 6

You can do something like that:

def last_day_of_month?
   (Time.zone.now.month + 1.day) > Time.zone.now.month
end

Time.zone.now.day if last_day-of_month?