php 声明一个二维数组

$twoDimensionalArray = array(
    array(1, 2, 3),
    array(4, 5, 6),
    array(7, 8, 9)
);

$twoDimensionalArray = array();
for ($i = 0; $i < 3; $i++) {
    $twoDimensionalArray[$i] = array();
    for ($j = 0; $j < 3; $j++) {
        $twoDimensionalArray[$i][$j] = $i * 3 + $j + 1;
    }
}

$twoDimensionalArray = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
];

if (isset($twoDimensionalArray[$i][$j])) {
    echo $twoDimensionalArray[$i][$j];
} else {
    echo "Index out of bounds";
}

foreach ($twoDimensionalArray as $row) {
    foreach ($row as $value) {
        echo $value . " ";
    }
    echo "<br>";
}