PHPで転置行列

            <div class="section">

<?php
$matrix = array(
array(1, 2, 3),
array(4, 5, 6),
array(7, 8, 9),
);
print_matrix($matrix);
print_matrix(transpose($matrix));
function transpose($matrix) {
$transpose = null;
foreach ($matrix as $row_k => $row) {
foreach ($row as $col_k => $col) {
$transpose[$col_k][$row_k] = $col;
}
}
return $transpose;
}
function print_matrix($matrix) {
echo "----- Print matrix -----\n";
foreach ($matrix as $row) {
foreach ($row as $col) {
echo $col . ' ';
}
echo "\n";
}
}