Simple IBAN checker
Load the lib:
require 'simpleiban'
Create a new IBAN to check:
a = IBAN.new 'GB82 West 12345 69876 5432' # from wikipedia
Is it valid (according to the rules)?
a.valid?
And pretty_print it (as a string):
str = a.to_s
# str = "GB82 WEST 1234 5698 7654 32"