如何在PHP中取消设置空数组？

Question

i have an array $mainArray of arrays and i would like to remove / undset the arrays that vave keys with no value.

here is my array:

Array
(
[0] => Array
    (
        [msg_id] => 203
        [comment] => Array
            (
                [0] => Array
                    (
                        [com_id] => 
                    )
            )
    )
[1] => Array
    (
        [msg_id] => 202
        [comment] => Array
            (
                [0] => Array
                    (
                        [com_id] => 196
                    )
                [1] => Array
                    (
                        [com_id] => 197
                    )
                [2] => Array
                    (
                        [com_id] => 
                    )
            )
    )
[2] => Array
    (
        [msg_id] => 201
        [comment] => Array
            (
                [0] => Array
                    (
                        [com_id] => 198
                    )
                [1] => Array
                    (
                        [com_id] => 
                    )
            )
    )
)

In this case i would like to look inside comment array arrays and see if there are any of them that have empty values. The best case scenario would be to remove the comment array entirely if all sub arrays are empty.

nut im of with leaving the comment hey there just null

this array should become:

Array
(
    [0] => Array
        (
            [msg_id] => 203
        )
    [1] => Array
        (
            [msg_id] => 202
            [comment] => Array
                (
                    [0] => Array
                        (
                            [com_id] => 196
                        )
                    [1] => Array
                        (
                            [com_id] => 197
                        )
                )
        )
    [2] => Array
        (
            [msg_id] => 201
        )
)

any ideas on how to proceed?

thanks.

Answer 1

Use php's unset() to unset any array key/value.

More info on this link http://in3.php.net/unset

in your case the code can be, (i have not tested it. but let me know if you have any problem and i can fix it)

function unsetCommentFromArray($mainArray) {
    foreach($mainArray as $key => $value) {
        foreach($value['comment'] as $k => $v) {
            if(empty($v['com_id'])) {
                unset($mainArray[$key]['comment'][$k]);
            }
        }   
    }
    return $mainArray;
}

Answer 2

array_filter() is what you're after. Particularly a recursive version. The following was taken from a comment on the PHP Doc :.

function array_filter_recursive($array, $callback = null) {
    foreach ($array as $key => & $value) {
        if (is_array($value)) {
            $value = array_filter_recursive($value, $callback);
        }
        else {
            if ( ! is_null($callback)) {
                if ( ! $callback($value)) {
                    unset($array[$key]);
                }
            }
            else {
                if ( ! (bool) $value) {
                    unset($array[$key]);
                }
            }
        }
    }
    unset($value);

    return $array;
}

Answer 3

$array = array_map(function ($i) {
    $i['comment'] = array_filter($i['comment'], function ($c) { return $c['com_id']; });
    return array_filter($i);
}, $array);

Requires PHP 5.3 or higher.