B.2 Nested Data Structures

Each array or hash is a collection of scalars, some or all of which can be references to other structures.

7. Lists do not nest like this:

   @foo = (1, 3, ("hello", 5), 5.66);

   For nesting, make the third element a reference to an anonymous array:

   @foo = (1, 3, ["hello", 5], 5.66);       

8. An example of a nested data structure (a hash of array of hashes):

   $person = {   # Anon. hash    "name" => "John",  # '=>' is an alias for a comma    "age"  => 23,    "children" => [  # Anonymous array of children                      {                         "name" => "Mike",  "age"  => 3,                      },                      {                         "name"  => "Patty","age"   => 4                      }                  ]    }; print $person->{age}                 ; # Print John's age print $person->{children}->[0]->{age}; # Print Mike's age print $person->{children}[0]{age}    ; # Print Mike's age, omitting                                        # arrows between subscripts

9. To pretty-print $person above:

    use Data::Dumper;  Data::Dumper->Dumper($person);  # Or,  require dumpVar.pl;  main::dumpValue($person);