iterator.rb

require 'active_support/all'

from = "01/01/2012".to_date
to = "31/12/2012".to_date
tmp = from
count = 0

begin
  tmp += 1.day
  count += 1 unless tmp.saturday? || tmp.sunday?
end while tmp <= to

puts count

require 'active_support/all'

from = "01/01/2012".to_date
to = "31/12/2012".to_date
days = (to - from).to_i
saturdays = (from..to).collect(&:saturday?).reject { |d| !d }.size
sundays = (from..to).collect(&:sunday?).reject { |d| !d }.size
days - sundays - saturdays

from = "01/01/2012".to_date
to = "31/12/2012".to_date
days = (from..to).reject(&:sunday?).reject(&:saturday?).size

from = "01/01/2012".to_date
to = "31/12/2012".to_date
days = (from..to).reject(&:sunday?).reject(&:saturday?).size