In this particular case, though, I'll bet a round of virtual drinks that performance isn't an issue, and that the split-into-three-lists routine gets called no more than a handful of times per CGI invocation.

Yeah I'd say performance probably doesn't really matter.

If it really isn't an issue then it would be better to rate the solutions on efficiency, maintainability, flexibility and coolness.

eg's solution may be the fastest in this set of benchmarks, but it doesn't include a variable number of buckets (which may be useful later in a project) and it isn't one the one that I personally (not begin a perl god) can understand and alter the fastest.

Maybe someone else can come up with a better, and overall rating....

I wasn't trying to say one person's code sucked over another's. I was just giving benchmark information. When we have a lot of code offered like that I like to see statistics like that sometimes. A good benchmark usually means the coder has a good understanding of what operations in Perl are more efficient, and took that into account when offering his solution. In my eyes that's the sign of a very good Perl coder!

Any arbitrary "rating" taking other aspects of their code into account would be incredibly subjective and not very useful. Readability is in the eye of the beholder, so to speak, so take a look at each of them and decide for yourself which one is the most elegant in your eyes for the efficiency it gets.

Fastolfe, could you post your benchmark code? Perhaps I am not using Benchmark.pm correctly, but I do not obtain similar standings.
thanks.

It's rather long, but here it is. By all means let me know if I've done something wrong.

I've removed the code because this node was really long and annoying. It's in the source code of the page if you want it, but it's out of date since others have been added since then.

aha: I should've asked for this myself. A couple things wrong with it:

1. the dws() routine shifts @array instead of @_, so all code that ran after it (everything but danger()) was passed an empty @array. This is the big source of differences.(dws() also needs fixing to return the actual buckets).
2. the repson() routine does a my @array = shift when it should do a my @array = @_ (only affects its own standing).

below are corrected dws() and repson() routines, and I've taken this opportunity to include a fix for my silly holdover in my danger() routine:

sub dws {
    my $nbuckets = 3;#shift;  # number of buckets to divide @array int
+o
    my @bucket;        # @{$bucket{0 .. $nbuckets - 1}} are the bucket
+s

    foreach my $n( 0 .. $nbuckets - 1) {
        foreach my $size (1 .. int(0.9999 + @_ /($nbuckets - $n))){
            push @{$bucket[$n]}, shift @_;
        }
    }
    return @bucket;
}
sub repson {
    my @array = @_;
    my $num = 3;                    # buckets

    my $cnt = @array;               # total items
    my $base = int($cnt/$num);      #  }
    my $left = $cnt % $num;         #  } $cnt = ($base * $num) + $left

    my @buckets;
    for (1..$num) {
            push @buckets, [ splice(@array,0,$base + ($left-- > 0 && 1
+) ) ];
    }
    @buckets;
}
sub danger_fixed {
    my $buckets = shift;
    my @list    = @_;
    my $mod     = @list % $buckets;
    my $inc     = int(@list / $buckets);
    map{ [splice @list, 0, $inc + (--$mod >= 0)] } 0 .. $buckets - 1;
}

relative results:

           Rate  dws tilly   eg fast_sp2 tillyr danger repson fast_sp1
+ danger1 fastolfe
dws      1034/s   --   -1% -18%     -32%   -34%   -36%   -36%     -40%
+    -42%     -52%
tilly    1043/s   1%    -- -17%     -31%   -33%   -35%   -35%     -39%
+    -42%     -52%
eg       1263/s  22%   21%   --     -17%   -19%   -21%   -22%     -27%
+    -30%     -42%
fast_sp2 1516/s  47%   45%  20%       --    -3%    -5%    -6%     -12%
+    -16%     -30%
tillyr   1564/s  51%   50%  24%       3%     --    -3%    -3%      -9%
+    -13%     -28%
danger   1604/s  55%   54%  27%       6%     3%     --    -1%      -7%
+    -11%     -26%
repson   1613/s  56%   55%  28%       6%     3%     1%     --      -6%
+    -10%     -26%
fast_sp1 1723/s  67%   65%  36%      14%    10%     7%     7%       --
+     -4%     -21%
danger1  1796/s  74%   72%  42%      18%    15%    12%    11%       4%
+      --     -17%
fastolfe 2174/s 110%  108%  72%      43%    39%    36%    35%      26%
+     21%       --
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