>perl -MData::Dumper -e"grep { 0 } @h{qw(a b)}; print Dumper \%h;"
$VAR1 = {
          'a' => undef,
          'b' => undef
        };

##</code><code>##

my @defined_values = map $benchmarks{$_},
                     grep defined($benchmarks{$_}),
                     @BASELINES;

##</code><code>##

my @defined_values = map $benchmarks{$_},
                     grep exists($benchmarks{$_}),
                     @BASELINES;