From: Jamis Buck <jgb3@...>
Date: 2004-08-21T04:44:06+09:00
Subject: Re: Neat trick for Steckerboard of Enigma needed...

Meino Christian Cramer wrote:
> Hi Rubyaner !  :)
> 
>    The Steckerboard is a patch panel on some models of the Enigma.
> 
>    If letters are "steckered" (oh, what do I like this language-mixed
>    words! GREAT! :), then they will be swapped while encoding.
> 
>    For example: If "AG" is steckered, pressing "A" on the keyboard
>    will feed "G" into the Enigma and -- on the way out of the Enigma,
>    each "G" is translated into an "A" as the last step of
>    encryption. Letters, which are not steckered (they are
>    "selfsteckered") remain unswapped. 
> 
>    From the user point of view s/he will feed zero to max 13 pairs of
>    letters to the simulator on the commandline. Each can only appear
>    once.
> 
>    So I get a string, for example "AGQTRXDF" into the simulator.
>    
>    Does anyone of the Ruby gurus here know a neat trick to convert
>    this into a hash of the form
>    
>    steckers={
> 		"A" => "G",
> 		"Q" => "T",
> 		"R" => "X"
> 		"D" => "F"
>    }    
>    
>    in "one turn"? I only know a very "unrubyish" way to do this in
>    single steps -- kinda "slow motion" programming... ;)
> 

Something like this, perhaps?

"AGQTRXDF".scan(/(.)(.)/).inject(Hash.new) { |h,m| h[m[0]] = m[1]; h }

- Jamis


>    As always thank you very much for your friendly help in advance!
>    Meino
> 
>    
> 
> .
> 


-- 
Jamis Buck
jgb3@email.byu.edu
http://www.jamisbuck.org/jamis

"I use octal until I get to 8, and then I switch to decimal."