Ruby routing number check sum function

routing_number_check_sum.rb

# Ruby routing number check sum function.  Code adapted from Wikipedia Python
# example: http://en.wikipedia.org/wiki/Routing_transit_number

# Returns true if a routing number string check sum is valid. 
def routing_number_check_sum(number)
    d = []
    number.each_char { |char| d << char.to_i }

    d[8] == (7 * (d[0] + d[3] + d[6]) +
             3 * (d[1] + d[4] + d[7]) +
             9 * (d[2] + d[5])
            ) % 10
end

# List of valid routing numbers
list = %w(211170363 065000090 065001426 065002030 065002548 111904451 065200243)

list.each do |number|
    puts "#{number} is valid: #{routing_number_check_sum(number)}"
end