Variables

• $var
• A simple scalar variable.
• $var[28]
• 29th element of array @var.
• $p = \@var
• Now $p is a reference to array @var.
• $$p[28]
• 29th element of array referenced by $p.

  Also, $p->[28].

• $var[-1]
• Last element of array @var.
• $var[$i][$j]
• $j-th element of $i-th element of array @var.
• $var{'Feb'}
• A value from hash (associative array) %var.
• $p = \%var
• Now $p is a reference to hash %var.
• $$p{'Feb'}
• A value from hash referenced by $p.

  Also, $p->{'Feb'}.

• $#var
• Last index of array @var.
• @var
• The entire array; in a scalar context, the number of elements in the array.
• @var[3,4,5]
• A slice of array @var.
• @var{'a','b'}
• A slice of %var; same as ($var{'a'},$var{'b'}).
• %var
• The entire hash; in a scalar context, true if the hash has elements.
• $var{'a',1,...}
• Emulates a multidimensional array.
• ('a'...'z')[4,7,9]
• A slice of an array literal.
• pkg::var
• A variable from a package, e.g., $pkg::var, @pkg::ary.
• \object
• Reference to an object, e.g., \\$var, \\%hash.
• *name
• Refers to all objects represented by name.

  *n1 = *n2 makes n1 an alias for n2.

  *n1 = $n2 makes $n1 an alias for $n2.

You can always use a { block } returning the right type of reference instead of the variable identifier, e.g., ${...}, &{...}. $$p is just a shorthand for ${$p}.