From: charlie.mills@...
Date: 2003-12-04T04:26:24+09:00
Subject: Re: strings and ranges

                                                                                                                                  
                      "David A. Black"                                                                                            
                      <dblack@wobblini         To:      ruby-talk@ruby-lang.org (ruby-talk ML)                                    
                      .net>                    cc:                                                                                
                                               Subject: Re: strings and ranges                                                    
                      12/03/2003 10:48                                                                                            
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Hi --

On Thu, 4 Dec 2003 charlie.mills@milliman.com wrote:

> The following program doesn't execute as I would expect:
>
> #!/usr/bin/ruby
>
> stringy = "X"
>
> 1.upto(10) do |i|
>   puts stringy
>   stringy.succ!
> end
>
> "X".upto("AG") do |ss|
>   puts ss
> end
>
> puts "'AB' > 'AA' = #{'AB' > 'AA'}"
> puts "'X' < 'AA' = #{'X' < 'AB'}"

Interesting -- just like "9" and "10" (i.e., "9" > "9".succ).

> # The code below gets around my problem...
>
> stringy = "X"
> while true
>   puts stringy
>   stringy.succ!
>   break if stringy == "AH"
> end
>
> # Is there a better way?

How about this:

  x = "X"
  puts (0...10).map { x.succ! .dup }

(You need the .dup or you'll end up with 10 of x, all the same
string.)

--
That works.
I guess I also want to capture the ability to iterate until you reach a
given string.
So the problem with going through the range 0...10 is you have to have a
way of mapping "X" to 0 and "AG" to 10 (or to two numbers whose difference
is 10).
(I guess you also have to know that "Z".succ -> "AA", and that "X" and "AG"
are of the form /[A-Z]+/)

-Charlie



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