Pointers and references: Difference between revisions

References are essentially how perl handles pointers. Any scalar value, element in an array, key of a hash, or value of a hash may contain a reference to any other variable structurer.

# start with some var definitions

my $scalar = 'a string';

my @array = ('an', 'array');

my %hash = ( firstkey => 'a', secondkey => 'hash' );

# make pointers

my $scalarref = \$scalar;

my $arrayref = \@array;

my $hashref = \%hash;

# printing the value

print ${$scalar};

print $arrayref->[1]; # this would print "array"

print $hashref->{'secondkey'}; # this would print "hash"

# changing the value

${$scalar} = 'a new string'; # would change $scalar as well

$arrayref->[0] = 'an altered'; # would change the first value of @array as well

$hashref->{'firstkey'} = 'a good'; # would change the value of the firstkey name value pair in %hash

my $scalarref;

${$scalarref} = 'a scalar';

my $arrayref = ['an', 'array'];

my $hashref = { firstkey => 'a', secondkey => 'hash' }