Re: Concept map of data types

[Marshall]

There are many things that are <s>completely/<s> very wrong.
There are many things that are not right. Let's start with LOL, List of List (Array of Array):

#!usr/bin/perl -w
use strict;

#LISTS OF LISTS (array of array)

my @abc =  #abc is an array of references to arrays
( 
    [ qw (q   w  e  r)  ],
    [ qw (1   x  3  r)  ],
    [ qw (qwe rt 434 )  ],
);

foreach my $array_ref (@abc)
{
   print "@$array_ref \t";
   print "third element: \t", $array_ref->[2],"\n";
}

__END__
Prints:
q w e r     third element:  e
1 x 3 r     third element:  3
qwe rt 434  third element:  434

<Update:>

Many instructors talk about list of list versus array of array.
This is not a "terrible thing".
There is actually a rather fine difference between these two concepts.

[programmer.perl]

I added your example to the concept map. It is a good another example of array of arrays. Also, I wrote and added this lines to the section 'HASH OF HASHES WITH LISTS OF VALUES'

push @{$ref->{'key1'}->{'key2'}}, "@{$adds}"; 
      # anonymous array: $adds = ["e","f"];
print "@{$ref->{'key2'}->{'key'}}"; # output: c d e f

I found useful 'perldoc perl...', till time I was searching for any info in the Internet.