I probably would have used a fisher-yates shuffle or the shuffle() from List::Util.

Benchmarking shows that the XS version is much, much faster than anything done in Perl. But if you stick to a Perl solution, one that acts on an array instead of a list is the winner. Here are some benchmark results, followed by the benchmark itself. Note the dramatic decrease in performance of 'coruscate' when the lenght of the list to be sorted increases - this is due to the splicing, which results in a quadratic algorithm; all other solutions are linear.

Benchmarking with a deck of 13.
              Rate     roger coruscate    fisher   fisher2      list
roger      18931/s        --       -0%       -4%      -21%      -85%
coruscate  18959/s        0%        --       -4%      -20%      -85%
fisher     19747/s        4%        4%        --      -17%      -85%
fisher2    23821/s       26%       26%       21%        --      -82%
list      129419/s      584%      583%      555%      443%        --
Benchmarking with a deck of 52.
             Rate    fisher     roger coruscate   fisher2      list
fisher     4917/s        --       -2%       -3%      -18%      -85%
roger      5021/s        2%        --       -1%      -17%      -85%
coruscate  5062/s        3%        1%        --      -16%      -85%
fisher2    6031/s       23%       20%       19%        --      -82%
list      33210/s      575%      561%      556%      451%        --
Benchmarking with a deck of 1024.
            Rate coruscate    fisher     roger   fisher2      list
coruscate  246/s        --       -2%       -6%      -21%      -86%
fisher     251/s        2%        --       -4%      -19%      -86%
roger      261/s        6%        4%        --      -16%      -85%
fisher2    310/s       26%       23%       19%        --      -82%
list      1767/s      619%      603%      577%      471%        --
Benchmarking with a deck of 50000.
             Rate coruscate    fisher     roger   fisher2      list
coruscate 0.909/s        --      -72%      -73%      -85%      -94%
fisher     3.19/s      251%        --       -7%      -47%      -78%
roger      3.43/s      277%        7%        --      -43%      -76%
fisher2    6.03/s      563%       89%       76%        --      -58%
list       14.3/s     1474%      349%      318%      137%        --


#!/usr/bin/perl

use strict;
use warnings;

use List::Util;
use Benchmark qw /timethese cmpthese/;

our (@cards, @cards2, @tmp);

foreach my $size (qw /13 52 1024 50000/) {

    @cards  = 1 .. $size;
    @cards2 = 1 .. $size;

    print "Benchmarking with a deck of $size.\n";

    cmpthese -10   => {
        roger      =>  '@tmp = roger               @cards',
        coruscate  =>  '@tmp = coruscate           @cards',
        fisher     =>  '@tmp = fisher              @cards',
        fisher2    =>  '       fisher2            \@cards2',
        list       =>  '@tmp = List::Util::shuffle @cards',
    };

}


sub roger {
    my @new = ();

    for (@_) {
        my $i = int rand($#new+1);
        push @new, $new[$i];
        $new[$i] = $_;
    };

    return(@new);
}

sub coruscate {
  my @orig_deck = @_;
  my @new_deck;

  for (0 .. $#orig_deck) {
    my $rand = int(rand $#orig_deck);
    push @new_deck, splice(@orig_deck, $rand, 1);
  }

  return @new_deck;
}
        
        
sub fisher {
    my $i = my @deck = @_;
    while (-- $i) {
        my $j = int rand ($i + 1);
        @deck [$i, $j] = @deck [$j, $i];
    }
    @deck;
}
    

sub fisher2 { 
    my $deck = shift;
    my $i    = @$deck;
    while (-- $i) {   
        my $j = int rand ($i + 1);
        @$deck [$i, $j] = @$deck [$j, $i];
    }
}
__END__
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Abigail

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