Can't use an undefined value as an ARRAY reference

##</code><code>##

 my $data = data();
 my $count = scalar(@$data); #  $#$data;
print $count;

##</code><code>##

It does not work if the array ref returns nothings
 my $data = data();
 my $count = scalar(@$data); #  $#$data;
print $count;

##</code><code>##

my @count = $data;
my $count = @count;
print $count;