使用一个for循环将N*N的二维数组的所有值置1

$n = 3;
$a = [];

for($i=0;$i<$n*$n;$i++){

    $a[$i/$n][$i%$n] = 1;
}

echo "<pre>";print_r($a);

运行结果：

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 1
            [2] => 1
        )

    [1] => Array
        (
            [0] => 1
            [1] => 1
            [2] => 1
        )

    [2] => Array
        (
            [0] => 1
            [1] => 1
            [2] => 1
        )

)