reference to array, use -> to get element, reference to hash

my @skipper = qw(blue_shirt hat jacket preserver sunscreen);
my @skipper_with_name = ('Skipper', \@skipper);
my @professor = qw(sunscreen water_bottle slide_rule batteries radio);
my @professor_with_name = ('Professor', \@professor);
my @gilligan = qw(red_shirt hat lucky_socks water_bottle);
my @gilligan_with_name = ('Gilligan', \@gilligan);


my @all_with_names = (
  \@skipper_with_name,
  \@professor_with_name,
  \@gilligan_with_name,
);

print "${$all_with_names[1]}[0]\n";
print "@{$all_with_names[1]}\n";

#Professor
#Professor ARRAY(0x8c351ec)

my @array = (1, 2 );
 my $ref = \@array;
 $ref->[0]=100;
 print @array;
#1002

$root = \@all_with_names;
print "$root->[1]->[1]->[2]\n";
print "$root->[1][1][2]\n";
#slide_rule
#slide_rule

Reference to hash

my %gilligan_info = (
  name     => 'Gilligan',
  hat      => 'White',
  shirt    => 'Red',
  position => 'First Mate',
);
my $hash_ref = \%gilligan_info;
my @keys = keys % { $hash_ref };#get the keys.
my $name = $ { $hash_ref } { 'name' }; #Gilligan

As with array references, we can use shortcuts to replace the complex curly-braced forms under some circumstances. For example, if the only thing inside the curly braces is a simple scalar variable (as shown in these examples so far), we can drop the curly braces:

my $name = $$hash_ref{'name'};
my @keys = keys %$hash_ref;

Like an array reference, when referring to a specific hash element, we can use an arrow form:

my $name = $hash_ref->{'name'};

my %gilligan_info = (
  name     => 'Gilligan',
  hat      => 'White',
  shirt    => 'Red',
  position => 'First Mate',
);
my %skipper_info = (
  name     => 'Skipper',
  hat      => 'Black',
  shirt    => 'Blue',
  position => 'Captain',
);
my @crew = (\%gilligan_info, \%skipper_info);



Thus, $crew[0] is a hash reference to the information about Gilligan. We can get to Gilligan's name via any one of:

${ $crew[0] } { 'name' }
my $ref = $crew[0]; $$ref{'name'}
$crew[0]->{'name'}
$crew[0]{'name

my $format = "%-15s %-7s %-7s %-15s\n"; printf $format, qw(Name Shirt Hat Position); for my $crewmember (@crew) { printf $format, $crewmember->{'name'}, $crewmember->{'shirt'}, $crewmember->{'hat'}, $crewmember->{'position'}; }

we can use hash slice to output

for my $crewmember (@crew) {
  printf $format, @$crewmember{qw(name shirt hat position)};
}