my %hash ={"var1", "info1", "var2", "info2", "var3", "info3"};
my @array=("var1","var2","var3");
my $where = "var1";
my $used = 0;

foreach my $item(@array){
   if ($item eq $where)
   {
      push @result_array, $hash{$item};
      $used = 1;
   }
}
unless ($used = 1){
push @result_array, $where;
}
$used = 0;