code sample: possible improvements

[arcnon]

I have read that linked lists in perl are slow but I can't quite find an example of one.
Is this a linked list? If so how can I change it without losing any of the functionality?

#!/usr/bin/perl -w

use strict;
system('clear');

my @data;
$data[2] = 'hi there';

my %objREF;
$objREF{poker} = \$data[2];
 
 
print "struct example\n";
print "======================================\n";
print "original value:\n";
print_me();

print "change by array value:\n";
$data[2] = 'joker';
print_me();

print "change value by ref:\n";
${$objREF{poker}} = 'batman';
print_me();

print "change the array\n";
$data[2] = 'robin';
print_me();

sub print_me{
	print "array is: $data[2]\n";
	print "Ref is: ${$objREF{poker}}\n\n";
}

 

[PaulTEG]

AFAIK, linked lists are best supported by hashes, if you don't want it, delete it, then sort

Where did you hear they were slow?
--Paul

cigless ...

 

[mikevh]

No, what you posted is not a linked list.
Have you looked at this:
perldoc -q "linked list"

 

[arcnon]

Paul
from 1 of the perl books.... I think the perl cookbook is where I read it;

mike
no.... and I didn't even know how to use perldoc. thanks I'll have to look at that.

thanks again guys

 

[arcnon]

well I have run into a problem. After implementing my code I can't get at my data.

my $test = first();
two($test);

sub first{
	my @data;
	my %objREF;

	$data[2] = 'hi there';
	$objREF{poker} = \$data[2];
}

sub two{
	my $objREF = shift;
	
	#print "$objREF{'poker'}";
	#print "$$objREF{'poker'}";
	#print "$objREF->{'poker'}";
	#print "$$objREF->{'poker'}";
	#print "$$$objREF{'poker'}";
	#print "$$$$objREF{'poker'}";
	#print "${$objREF{'poker'}}\n";
	#print "$${$objREF->{'poker'}}\n";

}

What am I mising here

 

[rharsh]

arcnon, what kind of results/errors are you getting? Here is a modified version of the code you posted that should work for you.

my $test = first();
two($test);

sub first{
    my @data;
    my %objREF;

    $data[2] = 'hi there';
    $objREF{poker} = \$data[2];
    return \%objREF;
}

sub two{
    my $objREF = shift;
    print ${$objREF->{poker}}, "\n";
}

 

[stevexff]

When I'm messing about with nested data structures, particularly when they have been written by someone else, I normally use Data:umper for debugging.

use Data::Dumper;
...
...
my $ref = getRefToSomethingComplicated();

print Dumper($ref);

It shows arrays delimited by [...] and hashes by {...} in a nice nested format that lets you see what's going on.

 

[arcnon]

I restarted and it started working again. used my first ref like rharsh: ${$objREF->{poker}};

amazing what a restart will do.