Dereferencing

The process of accessing the data pointed to by a reference
Dereferencing is not automatic.
Example: printing a reference from the last section:

print "$ref_part $ref_inventory $ref_lunch \n";

would yield something like:

SCALAR(0x4a99f0) ARRAY(0x74b548) HASH(0x8054e8)

(hexadecimal representations of memory locations.)
Instead, explicitly dereference each reference.
For scalars, preface references with the scalar symbol, '$':

print $$ref_part; # prints 'sparkplug'

Refer to entire arrays or hashes with the corresponding symbols to dereference:

print "@$ref_inventory"; # prints 'batteries fluids bolts' foreach $key (keys %$ref_lunch) { # do some processing }

Refer to individual elements of an array or hash with the scalar dereferencer (why?):

print "$$ref_inventory[1]"; # prints 'fluids' print "$$ref_lunch{'tuesday'}"; # prints 'sandwich'

Equivalent, more legible notation:

# this code does the same as above print "$ref_inventory->[1]"; print "$ref_lunch->{'tuesday'}";