@matrix = (
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
); 
# Change 6, the element at row  1, column 2 to 100
$matrix[1][2] = 100;

##</code><code>##

$matrix{0}{2} = 100;
$matrix{1}{0} = 200;
$matrix{2}{1} = 300;