Question

How to calculate next and previous business days in Rails?

Answer 1

As far as I understand, this is what you are looking for? (tested it)

require 'date'
def next_business_day(date)
  skip_weekends(date, 1)
end    

def previous_business_day(date)
  skip_weekends(date, -1)
end

def skip_weekends(date, inc = 1)
  date += inc
  while date.wday == 0 || date.wday == 6
    date += inc
  end   
  date
end

You can test it as follows:

begin
  t = Date.new(2009,9,11) #Friday, today
  puts "Today: #{Date::DAYNAMES[t.wday]} #{Date::MONTHNAMES[t.mon]} #{t.day}"
  nextday = next_business_day(t)
  puts "Next B-day: #{Date::MONTHNAMES[nextday.mon]} #{nextday.day}"
  previousday = previous_business_day(nextday)
  puts "back to previous: #{Date::MONTHNAMES[previousday.mon]} #{previousday.day}"
  yesterday = previous_business_day(previousday)
  puts "yesterday: #{Date::MONTHNAMES[yesterday.mon]} #{yesterday.day}"  
end