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This is an excerpt from the latest version perlfaq4.pod, which
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4.46: How do I handle linked lists?

In general, you usually don't need a linked list in Perl, since with
regular arrays, you can push and pop or shift and unshift at either end,
or you can use splice to add and/or remove arbitrary number of elements
at arbitrary points. Both pop and shift are O(1) operations on Perl's
dynamic arrays. In the absence of shifts and pops, push in general needs
to reallocate on the order every log(N) times, and unshift will need to
copy pointers each time.

If you really, really wanted, you could use structures as described in
perldsc or perltoot and do just what the algorithm book tells you to do.
For example, imagine a list node like this:

$node = {
VALUE => 42,
LINK => undef,

You could walk the list this way:

print "List: ";
for ($node = $head; $node; $node = $node->{LINK}) {
print $node->{VALUE}, " ";
print "\n";

You could add to the list this way:

my ($head, $tail);
$tail = append($head, 1); # grow a new head
for $value ( 2 .. 10 ) {
$tail = append($tail, $value);

sub append {
my($list, $value) = @_;
my $node = { VALUE => $value };
if ($list) {
$node->{LINK} = $list->{LINK};
$list->{LINK} = $node;
else {
$_[0] = $node; # replace caller's version
return $node;

But again, Perl's built-in are virtually always good enough.


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