```Begin forwarded message:

> From: "Harry Kakueki" <list.push / gmail.com>
> Date: May 2, 2007 10:46:47 PM CDT
> To: "James Edward Gray II" <james / grayproductions.net>
> Subject: Re: Ruby Quiz solution
>
> On 5/3/07, James Edward Gray II <james / grayproductions.net> wrote:
>> On May 2, 2007, at 8:27 PM, Harry Kakueki wrote:
>>
>> > I submitted a solution to Ruby Quiz a few minutes after the end
>> of the
>> > No-Spoiler period but my name is not listed under Quiz Solutions.
>> > Does that mean there is something wrong with my solution?
>>
>> I'm sorry Harry.  I don't see the solution on Ruby Talk or in my
>> personal mail.  If you resend I'll sure watch for it.  Sorry I missed
>> it.
>>
>> James Edward Gray II
>>
>
> No problem.
> I just wanted to understand what happened.
> Thanks.
>
> Here is my solution.
>
> ######
> # Check Starting numbers and length
> def card_ok(str,info)
> check = "UNKNOWN"
> info.each do |t|
> pref = t[0]
> leng = t[1]
> name = t[2]
>   pref.each do |x|
>     if x == str.slice(0...x.length)
>       leng.each do |y|
>         if y.to_i == str.length
>         check = name.dup
>         end
>       end
>     end
>   end
> end
> return check
> end
>
> # Check Luhn algorithm
> def luhn(str)
> luhn_hash = Hash.new("INVALID")
> if str.length != 0
> luhn_hash[0] =  "VALID"
> arr = str.split(//).reverse
> arr2 = []
> arr3 = []
>   (0...arr.length).each do |u|
>   arr2 << arr[u] if u %2 == 0
>   arr2 << (arr[u].to_i * 2).to_s if u %2 != 0
>   end
>
>   arr2.each do |r|
>   arr3 << r.split(//).inject(0) {|sum,i| sum + i.to_i}
>   end
>
> val = arr3.inject(0) {|sum,i| sum + i} % 10
> end
> return luhn_hash[val]
> end
>
> # Card information
> test = []
> test << [["31","34"],["15"],"AMEX"]
> test << [["6011"],["16"],"DISCOVER"]
> test << [("51".."55").to_a,["16"],"MASTERCARD"]
> test << [["4"],["13","16"],"VISA"]
> #test << [("3528".."3589").to_a,["16"],"JCB"]
> #test << [[("3000".."3029").to_a + ("3040".."3059").to_a +
> #("3815".."3889").to_a + ["36","389"]].flatten!,["14"],"DINERS"]
>
> # Main
> str = ARGV.join
> arr = []
> arr << card_ok(str,test)
> arr << luhn(str)
> puts arr
>
> Harry
>
> --
> http://www.kakueki.com/ruby/list.html
> A Look into Japanese Ruby List in English

```