如何在PHP中的关联数组中插入新的键值对? [关闭]

I've an associative array named $classes_data as follows:

Array
(
    [2] => Array
        (
            [class_id] => 2
            [class_name] => II
            [subjects] => Array
                (
                    [0] => 11 Engllish
                )

        )

    [3] => Array
        (
            [class_id] => 3
            [class_name] => III
            [subjects] => Array
                (
                    [0] => Hidi
                    [1] => 11 Maths
                    [2] => 11 Science
                    [3] => 11 Engllish
                )

        )

    [4] => Array
        (
            [class_id] => 4
            [class_name] => IV
            [subjects] => Array
                (
                    [0] => Physics
                )

        )

    [6] => Array
        (
            [class_id] => 6
            [class_name] => VI
            [subjects] => Array
                (
                    [0] => Mathematics
                    [1] => dfadadadsagfasrsarasrarBiology
                )

        )

    [7] => Array
        (
            [class_id] => 7
            [class_name] => VII
            [subjects] => Array
                (
                    [0] => Physics
                    [1] => Chemistry11
                    [2] => 11 Science
                )

        )

    [8] => Array
        (
            [class_id] => 8
            [class_name] => VIII
            [subjects] => Array
                (
                    [0] => Hidi
                    [1] => 11 Engllish
                )

        )

    [9] => Array
        (
            [class_id] => 9
            [class_name] => IX
            [subjects] => Array
                (
                    [0] => Mathematics
                    [1] => Hidi
                    [2] => 11 Science
                )

        )

)

The keys of array (viz. 2,3,4,6,7,8,9) are in this manner instead of 0,1,2,3,4,5,6 because I've used one function to rearrange these keys.

Now what I want to do is insert a new key class_checked and set its initial value as 0 (i.e.class_checked =>"0").

I tried lot of tricks but couldn't get the desired array format. Can any one help me in this to get the desired array? Thanks in advance.

For your information the required array format for array $classes_data will be as follows:

 Array
    (
    [2] => Array
        (
            [class_id] => 2
            [class_name] => II
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => 11 Engllish
                )

        )

    [3] => Array
        (
            [class_id] => 3
            [class_name] => III
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Hidi
                    [1] => 11 Maths
                    [2] => 11 Science
                    [3] => 11 Engllish
                )

        )

    [4] => Array
        (
            [class_id] => 4
            [class_name] => IV
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Physics
                )

        )

    [6] => Array
        (
            [class_id] => 6
            [class_name] => VI
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Mathematics
                    [1] => dfadadadsagfasrsarasrarBiology
                )

        )

    [7] => Array
        (
            [class_id] => 7
            [class_name] => VII
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Physics
                    [1] => Chemistry11
                    [2] => 11 Science
                )

        )

    [8] => Array
        (
            [class_id] => 8
            [class_name] => VIII
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Hidi
                    [1] => 11 Engllish
                )

        )

    [9] => Array
        (
            [class_id] => 9
            [class_name] => IX
            [class_checked] => 0
            [subjects] => Array
                (
                    [0] => Mathematics
                    [1] => Hidi
                    [2] => 11 Science
                )

        )

)

Try:

foreach($classes_data as $key=>$value) {
    $classes_data[$key]['class_checked'] = 0;
}
$array = array_map(function (array $i) { return $i + array('class_checked' => 0); }, $array);

Or:

foreach ($array as &$i) {
    $i['class_checked'] = 0;
}
unset($i);

given your initial $classes_data you could do this:

foreach($classes_data as &$class) {
  $class['class_checked'] = 0;
}

now the array should be as you want it to be.