in reply to work with Array of Arrays

It is relatively easier to print the number of rows and columns for a list of lists if all columns for each row are of the same count, if that is not the case then it is possible with a little bit more lines to count the number of columns for individual rows, I would advice you to read References quick reference and also these ones here perlcheat, perlref and perlreftut for related tutorials and quick cheats on references... 
#!/usr/local/bin/perl
use strict;
use warnings;

my @AoA=(
        [0, 1, 0, 0],
        [0, 0, 1, 0,0,0,0,0],
        [0, 0, 0, 1,0,1]
     );
 # my $row = scalar @AoA; ##Prints the number of rows for the array

for(my $i = 0; $i<=$#AoA;$i++){
        my $count =0;
        foreach my $column (@{$AoA[$i]}){
                $count ++;
                }
        print "Row# ", $i+1, " has $count columns\n";
        }

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Update: On the behest of almut's reply, the above code is just a prove of concept to ways to generally iterate over lists of lists, I wrote it in a rush while thinking of an approach similar to almut's, my code above unnecessarily loops over array elements just to do an incrementation... Here's a more efficient approach 
for(my $i = 0; $i<=$#AoA;$i++){
        my $count = @{$AoA[$i]};  
        print "Row #: ", $i+1, " has $count columns\n";
        }

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Re^2: work with Array of Arrays
by almut (Canon) on Apr 18, 2010 at 08:03 UTC 
        my $count =0;
    foreach my $column (@{$AoA[$i]}){
            $count ++;
            }

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    When all you do in the loop is increment, you might as well just write 

        my $count = @{$AoA[$i]};

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    which, btw, is approximately N times faster, with N being the size of the array: 

    use Benchmark 'cmpthese';

my @AoA;
$AoA[42] = [ (1) x 1000 ];

cmpthese(-1,
    {
        counted => sub {
            my $count =0;
            foreach my $column (@{$AoA[42]}){
                    $count ++;
                    }
        },
        direct  => sub {
            my $count = @{$AoA[42]};
        },
    }
);

__END__
             Rate counted  direct
counted   11821/s      --   -100%
direct  9267717/s  78297%      --

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