Re: Elegance, dammit!

In real life, I would normally use a splice like Errto and jdporter.

Before *any* solution, I would put:

die if @ref / 3;
[download]

Most elegant, non-destructive Perl5 solution I could think of:

my %out = map  { $ref[$_] => [ @ref[$_+1..$_+2] ] }
          grep { not $_ % 3 }
          0 .. $#ref;
[download]

Even better, but requires Perl6:

for @ref -> $key, $val1, $val2 {
    %out{$key} = [ $val1, $val2 ];
}
[download]

Update: Better yet, this also works in Perl6:

my %out = map -> $k, $v, $w {
    $k => [ $v, $w ];
}, @ref;
[download]

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Re^2: Elegance, dammit! by oko1 (Deacon) on Jun 16, 2007 at 02:58 UTC
Ah-HAH! :) (I really liked that Perl6 solution, BTW; I see that I'm going to have to get off my lazy butt and dig into it.) All of that - particularly Util's solution - has finally caused a reticent neuron to fire. Originally, I thought of this: `$out{shift @ref} = [splice @ref,0,2] while @ref;` [download] ...but there's a precedence problem with that, so that %out ends up containing stuff like `2 => [ 0, 1 ], 5 => [ 3, 4 ] etc.` [download] so my final cut at it ends up being this: `die if @ref % 3; $out{$a} = [splice @ref,0,2] while $a = shift @ref;` [download] I'm definitely up for seeing more solutions, though. You folks come up with some very pretty thought patterns. :) Thank you all!	[reply] [d/l] [select]
Re^2: Elegance, dammit! by moritz (Cardinal) on Jun 16, 2007 at 09:10 UTC
I can't resist offering a shorter Perl 6-solution: `my %out = map {$^k => [$^v, $^w]}, @ref;` The `^` secondary sigil ("twigil") is a self declaring formal paramter, all of the variables starting with `$^` will be filled in the block in lexicographic order. Perl 6 in German	[reply] [d/l] [select]
Re^2: Elegance, dammit! by kyle (Abbot) on Jun 16, 2007 at 19:30 UTC
`die if @ref / 3;` I really like the idea of an assertion (especially during debugging), but I'd probably write it this way: `die 'Assertion failed: @ref not divisible by 3' if scalar @ref % 3;` [download] If I'm not mistaken, yours dies every time `@ref` has any elements.	[reply] [d/l] [select]