#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use Data::Dumper;

my $ref = [[1, 2, 3], [4, 5, 6]];

# Print an element.
say $ref->[1][1];

# Add a row.
push @$ref, [7, 8, 9];

# Add a column.
my @column = (3.5, 6.5, 9.5);
push @{ $ref->[$_] }, $column[$_] for 0 .. $#column;

# The same with an array.
my @array = ([1, 2, 3], [4, 5, 6]);

# Print an element.
say $array[1][1];

# Add a row.
push @array, [7, 8, 9];

# Add a column.
my $column = \@column;
push @{ $array[$_] }, $column->[$_] for 0 .. $#$column;

Dumper($ref) eq Dumper(\@array) or die "Different";