date - Calculating the number of weeks in a year with Ruby

Question

Is there a way in Ruby to calculate the number of weeks(ISO 8601) for a given year? I'm currently using a lookup table and I'd like to stop using it.

Answer 1

def num_weeks(year = Date.today.year)
  Date.new(year, 12, 28).cweek # magick date!
end

long_iso_years = (2000..2400).select{|year| num_weeks(year) == 53} 

Yields the same list as wikipedia