math isn't easy...

nonetheless, its a good challenge

It's always time to learn some regex, but familiarity with str's methods can handle this one simply as well.

That work with Racket is coming in handy!

I'm a big python fan, but am really starting to like racket. I just wish more people would give it a go! I'm watching the s.i.c.p videos, and just had to check it out!

One thing that helps me alot, is make a list of the first 5 or more solutions. Then make a list of deltas for that list, another list of deltas for the delta list, and so on till I get a list that doesn't change. This really helps me see the patterns.

very cool. I wish katas like this would have a rank of say 7 to get functionality, then maybe 6 for the aha moment whey you recognise the patterns, and do it without a nested loop.
because the first job would be easy, you can start generating numbers . Then you see the first pattern... Then after a bit more work, the second one.
Overall, I like these kind of pattern recognition ones.

very cool, looking foward to 3d version.

This seemed SO easy,
many attemps later...
finally.

thank you for your help, using your example, I figured out where there was an error in the code and was finally able to solve it, as a result, the error was in a loop that multiplied two lists and gave incorrect values

I added one elif line where I mentioned mod==7 and number[8]=="X".

Hope it helps... I don't want to write the exact line. But it's a short line anyway...you'll make it :-)

For 3YC1DG6T7FY565964 the sum is 458, modulo is 4. for 5HVA1C6ZXPA702445 the modulo is 7. You should revise your code.

First example: translated "38314763768565964" =>

3 * 8 = 24

8 * 7 = 56

3 * 6 = 18

1 * 5 = 5

4 * 4 = 16

7 * 3 = 21

6 * 2 = 12

3 * 10 = 30

7 * 0 = 0

6 * 9 = 54

8 * 8 = 64

5 * 7 = 35

6 * 6 = 36

5 * 5 = 25

9 * 4 = 36

6 * 3 = 18

4 * 2 = 8

24+56+18+5+16+21+12+30+0+54+64+35+36+25+36+18+8 = 458

I'm having the same issue you had (only failing the first 3 tests). I recognize that each of these 3 VIN numbers have "X" as the checker digit, yet I still cannot figure out what I am doing wrong. Can you help explain to me how you were able to solve this?

I liked this kata a lot.

Coding is all about problem solving which this is ;).