in reply to Lewis Carroll's Code

Here are some thoughts I had about my code:
-- 
($_='jjjuuusssttt annootthheer
     pppeeerrrlll haaaccckkeer')=~y/a-z//s;print;

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Re: Re: Lewis Carroll's Code
by sauoq (Abbot) on Jul 18, 2002 at 04:10 UTC
    You might want to consider something like: 
        my @abc = ('a'..'z');
    my %abc = map { ($abc[$_],$_) } (0..25);
    my @key = map { $abc{ lc() } } $key =~ /([a-z])/ig;

    [download]
    To use it, loop through the characters in your message any way you like. The following assumes you have the current letter in $c , that $i holds your position in @key , and that the result will be in $result . . . 
            my $new_c;
        if ($c =~ /[a-z]/i) {
            $new_c =  $abc[($abc{lc($c)} + $key[$i]) % 26];
            $new_c = uc($new_c) if ($c =~ /[A-Z]/);
            $result .= $new_c;
            $i = ($i + 1) % @key;
        } else {
            $result .= $c;
        }

    [download]
    You could use the same code above for decoding if you changed @key to hold negative numbers instead of positives. 
    
-sauoq

"My two cents aren't worth a dime.";
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Re: Re: Lewis Carroll's Code
by cfreak (Chaplain) on Jul 18, 2002 at 04:15 UTC
    grep may be what you are looking for. it uses a regex rather than a string though:

    From the perldoc:

    grep BLOCK LIST
grep EXPR,LIST
     This is similar in spirit to, but not the same as,
     grep(1) and its relatives.  In particular, it is
     not limited to using regular expressions.

     Evaluates the BLOCK or EXPR for each element of
     LIST (locally setting "$_" to each element) and
     returns the list value consisting of those 
     ele­ments for which the expression evaluated to true.
     In scalar context, returns the number of times the
     expression was true.

     @foo = grep(!/^#/, @bar);    # weed out comments

     or equivalently,

     @foo = grep {!/^#/} @bar;    # weed out comments

    [download]

    Hope that helps
    Chris

    Lobster Aliens Are attacking the world!
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      I'm confused -- what is it you want me to use GREP for?
      -- 
      ($_='jjjuuusssttt annootthheer
     pppeeerrrlll haaaccckkeer')=~y/a-z//s;print;

      [download]
[reply]
[d/l]

        Sorry, I was saying that you could use grep() on an array like you would use index() on a string, its not exactly the same though.... I think I better go to bed I'm not making much sense and I'm getting myself downvoted :)

        Lobster Aliens Are attacking the world!
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