my @arr;
while (my ($x, $y, $beans) = read_grid_cell) {
    push @arr, [$x, $y, $beans];
}
# Or the equivalent map statement, if you like.

##</code><code>##

my %hash;
while (my ($x, $y, $beans) = read_grid_cell) {
    $hash{$x}{$y} = $beans;
}

##</code><code>##

my @beans;
my %grid;
while (my ($x, $y, $beans) = read_grid_cell) {
    push @beans, [$x, $y, $beans];
    $grid{$x}{$y} = $beans;
}
# Now you can walk through @beans, or you can lookup by $x and $y,
# but don't change the beans in either spot, because they're not linked!