Integer#digits speed

digits.rb

def time
  start_time = Time.now
  1000.times { yield }
  Time.now - start_time
end

class Integer
  def digits
    working_int, digits = self, Array.new
    until working_int.zero?
      digits.unshift working_int % 10
      working_int /= 10
    end
    digits
  end
end

# For Fixnum
time { 12345.to_s.split(//).map(&:to_i)  } # => 0.009108
time { 12345.to_s.split(//).map!(&:to_i) } # => 0.008999
time { 12345.to_s.scan(/./).map!(&:to_i) } # => 0.006667
time { 12345.to_s.each_char.map(&:to_i)  } # => 0.003874
time { 12345.digits                      } # => 0.001884


# For Bignum
num = 107150860718626732094842504906000181056140481170
time { num.to_s.split(//).map(&:to_i)  } # => 0.047821
time { num.to_s.split(//).map!(&:to_i) } # => 0.045045
time { num.to_s.scan(/./).map!(&:to_i) } # => 0.034497
time { num.to_s.each_char.map(&:to_i)  } # => 0.019096
time { num.digits                      } # => 0.03735

ENV['RUBY_VERSION'] # => "ruby-1.9.2-p180"