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A coworker came to me with a very simple question: How would you assign the maximum of two numbers? I.e., $a = the larger of $b and $c. Here's what I found:

            Rate    sort   sort2    loop ternary    List
sort    112734/s      --     -1%    -39%    -48%    -67%
sort2   113778/s      1%      --    -39%    -48%    -67%
loop    185579/s     65%     63%      --    -15%    -46%
ternary 217375/s     93%     91%     17%      --    -37%
List    344926/s    206%    203%     86%     59%      --
[download]

here's the benchmark script:

use List::Util qw(max);

sub assignmax {
    @a = sort{$b<=>$a}@_;
    shift @a;
}
sub assignmax5 {
    @a = sort@_;
    pop @a;
}

sub assignmax2 {
    ($b,$c) = @_;
    $b > $c ? $b : $c;
}

sub assignmax3 {
    max(@_);
}

sub assignmax4 {
    my $a=undef;
    for (@_) {
        $a = $_ if $_ > $a;
    }
    $a;
}

@r = map {int rand 1000}(0..1);


use Benchmark qw(cmpthese);
cmpthese -1,{
    'sort' => sub {assignmax(@r)},
    'sort2' => sub {assignmax5(@r)},
    'ternary' => sub {assignmax2(@r)},
    'List' => sub {assignmax3(@r)},
    'loop' => sub {assignmax4(@r)},
};
[download]

So, can you think of any other ways, and are any of them faster than List::Util?

update: for those who think this is too trivial a thought, so was watching mold grow until it was turned into penicillin.

In reply to assigning the maximum of two numbers by bageler

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