How to get the number of days in a given month in Ruby, accounting for year?

Question

I\'m sure there\'s a good simple elegant one-liner in Ruby to give you the number of days in a given month, accounting for year, such as \"February 1997\". What is it?

Answer 1

How about:

require 'date'

def days_in_month(year, month)
  (Date.new(year, 12, 31) << (12-month)).day
end

# print number of days in Feburary 2009
puts days_in_month(2009, 2)

You may also want to look at Time::days_in_month in Ruby on Rails.