How to calculate next, previous business day in Rails?

Question

How to calculate next and previous business days in Rails?

Answer 1

date = Date.today
date.next_weekday
date.prev_weekday

Answer 2

With the holidays-gem you can also check, if there is a public holiday. If you do so, you must define the region you need. The holidays-gem allows also to use subregions (e.g. us-va...)

An example code with German (de) and US-american (us) holidays.

require 'holidays'
require 'holidays/us'
require 'holidays/de'
require 'holidays/core_extensions/date'
class Date
  include Holidays::CoreExtensions::Date #provide Date#holiday?

  def next_business_day(region=:any)
    skip_weekends_and_holidays(1,region)
  end    

  def previous_business_day(region=:any)
    skip_weekends_and_holidays(-1,region)
  end

  def skip_weekends_and_holidays(inc, region = :any)
    date = self + inc
    while (date.wday == 6 or date.holiday?(region) ) do
      date += inc
    end   
    date
  end
end

Get attention: skip_weekends_and_holidays does not increment business days. If you increment 5 days from a Monday, you end on a Monday (unless this Monday is no holiday). If there was a holiday during the 5 days, there is additional increment.

Some test code:

[
  Date.new(2012,6,8), #Friday
  Date.new(2012,6,10), #Monday
  Date.new(2012,6,9), #Sunday
  Date.new(2012,12,24), #Christmas eve
  Date.new(2012,12,26), #After Christmas 
].each{|t|
  %w{us de}.each{|region|
    puts "====#{region}======"
    puts "Today: #{Date::DAYNAMES[t.wday]} #{Date::MONTHNAMES[t.mon]} #{t.day}"
    nextday = t.next_business_day(region)
    puts "Next B-day: #{Date::MONTHNAMES[nextday.mon]} #{nextday.day} - #{Date::DAYNAMES[nextday.wday]}"
    previousday = t.previous_business_day(region)
    puts "Previous B-day: #{Date::MONTHNAMES[previousday.mon]} #{previousday.day} - #{Date::DAYNAMES[previousday.wday]}"
  }

An extract from result (christmas eve):

====us======
Today: Monday December 24
Next B-day: December 26 - Wednesday
Previous B-day: December 23 - Sunday

Germany has two free days (25+26.12):

====de======
Today: Monday December 24
Next B-day: December 27 - Thursday
Previous B-day: December 23 - Sunday

---

Update: I made another version to determine multiple business days:

require 'holidays'
require 'holidays/us'
require 'holidays/core_extensions/date'
#~ require 'holidays/de'
class Date
  include Holidays::CoreExtensions::Date #provide Date#holiday?
  def next_business_day(region=:any)
    next_business_days(1,region)
  end    

  def next_business_days(inc, region=:any)
    date = self
    inc.times{
      date = date.next
      while (date.wday == 6 or date.holiday?(region) ) do
        date = date.next
      end
    }
    date
  end    

  def previous_business_day(region=:any)
    previous_business_days(1,region)
  end

  def previous_business_days(inc, region=:any)
    date = self
    inc.times{
      date = date.prev_day
      while (date.wday == 6 or date.holiday?(region) ) do
        date = date.prev_day
      end
    }
    date
  end    


end

My test code:

require 'test/unit'
class BDay_Test < Test::Unit::TestCase
  def test_2012_06_08_us()
    date = Date.new(2012, 6, 8)
    assert_equal( Date.new(2012, 06, 10), date.next_business_day('us'))
    assert_equal( Date.new(2012, 06,  7), date.previous_business_day('us'))

    assert_equal( Date.new(2012, 06, 17), date.next_business_days(7, 'us'))
    assert_equal( Date.new(2012, 05, 31), date.previous_business_day(7, 'us'))
  end
  def test_2012_06_08_de()
    date = Date.new(2012, 6, 8)
    assert_equal( Date.new(2012, 06, 10), date.next_business_day('de'))
    assert_equal( Date.new(2012, 06,  7), date.previous_business_day('de'))

    assert_equal( Date.new(2012, 06, 17), date.next_business_days(7, 'de'))
    assert_equal( Date.new(2012, 05, 31), date.previous_business_day(7, 'de'))
  end
  def test_2012_06_10_us()
    date = Date.new(2012, 6, 10)
    assert_equal( Date.new(2012, 06, 11), date.next_business_day('us'))
    assert_equal( Date.new(2012, 06,  8), date.previous_business_day('us'))

    assert_equal( Date.new(2012, 06, 18), date.next_business_days(7, 'us'))
    assert_equal( Date.new(2012, 06,  1), date.previous_business_day(7, 'us'))
  end
  def test_2012_06_10_de()
    date = Date.new(2012, 6, 10)
    assert_equal( Date.new(2012, 06, 11), date.next_business_day('de'))
    assert_equal( Date.new(2012, 06,  8), date.previous_business_day('de'))

    assert_equal( Date.new(2012, 06, 18), date.next_business_days(7, 'de'))
    assert_equal( Date.new(2012, 06,  1), date.previous_business_day(7, 'de'))
  end
  def test_2012_06_09_us()
    date = Date.new(2012, 6, 9)
    assert_equal( Date.new(2012, 06, 10), date.next_business_day('us'))
    assert_equal( Date.new(2012, 06,  8), date.previous_business_day('us'))

    assert_equal( Date.new(2012, 06, 17), date.next_business_days(7, 'us'))
    assert_equal( Date.new(2012, 06,  1), date.previous_business_day(7, 'us'))
  end
  def test_2012_06_09_de()
    date = Date.new(2012, 6, 9)
    assert_equal( Date.new(2012, 06, 10), date.next_business_day('de'))
    assert_equal( Date.new(2012, 06,  8), date.previous_business_day('de'))

    assert_equal( Date.new(2012, 06, 17), date.next_business_days(7, 'de'))
    assert_equal( Date.new(2012, 06,  1), date.previous_business_day(7, 'de'))
  end
  def test_2012_12_24_us()
    date = Date.new(2012, 12, 24)
    assert_equal( Date.new(2012, 12, 26), date.next_business_day('us'))
    assert_equal( Date.new(2012, 12, 23), date.previous_business_day('us'))

    assert_equal( Date.new(2013, 01,  3), date.next_business_days(7, 'us'))
    assert_equal( Date.new(2012, 12, 16), date.previous_business_day(7, 'us'))
  end
  def test_2012_12_24_de()
    date = Date.new(2012, 12, 24)
    assert_equal( Date.new(2012, 12, 27), date.next_business_day('de'))
    assert_equal( Date.new(2012, 12, 23), date.previous_business_day('de'))

    assert_equal( Date.new(2013, 01,  4), date.next_business_days(7, 'de'))
    assert_equal( Date.new(2012, 12, 16), date.previous_business_day(7, 'de'))
  end
  def test_2012_12_26_us()
    date = Date.new(2012, 12, 26)
    assert_equal( Date.new(2012, 12, 27), date.next_business_day('us'))
    assert_equal( Date.new(2012, 12, 24), date.previous_business_day('us'))

    assert_equal( Date.new(2013, 01,  4), date.next_business_days(7, 'us'))
    assert_equal( Date.new(2012, 12, 17), date.previous_business_day(7, 'us'))
  end
  def test_2012_12_26_de()
    date = Date.new(2012, 12, 26)
    assert_equal( Date.new(2012, 12, 27), date.next_business_day('de'))
    assert_equal( Date.new(2012, 12, 24), date.previous_business_day('de'))

    assert_equal( Date.new(2013, 01,  4), date.next_business_days(7, 'de'))
    assert_equal( Date.new(2012, 12, 17), date.previous_business_day(7, 'de'))
  end

end    

See test_2012_12_24_us() and date.next_business_days(7,... You end in 2013, each holiday in the period is respected.

Answer 3

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  

Answer 4

You may need to calculate business days in the future starting from a Saturday or Sunday. 1 business day after a Monday is the Tuesday, 1 business day from a Sunday should also be Tuesday - the starting weekend day should be ignored. The following achieves this:

class Date

  def business_days_future(inc)
    date = skip_weekend
    inc.times do
      date = date + 1
      date = date.skip_weekend
    end
    date
  end

  # If date is a saturday or sunday, advance to the following monday
  def skip_weekend
    if wday == 0
      self + 1
    elsif wday == 6
      self + 2
    else
      self
    end
  end

end