Filter out empty array elements of multidimensional array

Question

I'd like to filter an array which is created by converting XML to an array. I'd like to remove all parent keys of arrays with key = 0 and an empty value (f.e. "InvalidKey"), but not the ones with a custom name and no value (f.e. "column"). I've already used array_filter (even in combination with array_map), but those functions will filter too few or too much information from the array. I've also tried to create a loopable function to check if the current array has a key of 0 and an empty value, but I don't know how to get the parent key of the current array, f.e.:

Array
(
    [InvalidKey] => Array
        (
            [0] => *NULL*
        )
);

key($arrInput) = 0;
parent::key($arrInput) = "InvalidKey";

So, how to get from:

Array
(
    [test] => 
    [demo] => 524018
    [column] => 
    [xml] => Array
    (
        [Header] => Array
            (
                [0] => Array
                    (
                        [ValidKey] => Array
                            (
                                [0] => 1234
                            )

                        [InvalidKey] => Array
                            (
                                [0] =>
                            )
                    )

            )

        [Body] => Array
            (
                [0] => *NULL*
            )

        [Footer] => Array
            (
                [0] => Array
                    (
                        [ValidKey] => Array
                            (
                                [0] => I am valid
                            )

                        [MoreValidKey] => Array
                            (
                                [0] => I am valid too
                            )

                        [InvalidKey] => Array
                            (
                                [0] =>
                            )
                    )

            )

    )
)

To:

Array
(
    [test] => 
    [demo] => 524018
    [column] => 
    [xml] => Array
    (
        [Header] => Array
            (
                [0] => Array
                    (
                        [ValidKey] => Array
                            (
                                [0] => 1234
                            )
                    )

            )

        [Footer] => Array
            (
                [0] => Array
                    (
                        [ValidKey] => Array
                            (
                                [0] => I am valid
                            )

                        [MoreValidKey] => Array
                            (
                                [0] => I am valid too
                            )
                    )

            )

    )
)

PS: The used array key names are variable. For simplicity I used "(In)ValidKey". The array can be as much levels deep as possible, so I can't suffice with 2 for loops.

Answer 1

You need to write a custom script which checks all elements of your array.

Example:

<?php
$test = [
    [
        [
            "asdf",
            "",
            0,
            false,
            true,
            [
                "asdf",
                "",
                []
            ]
        ],
        []
    ],
    []
];

function removeEmptyElements(array $array)
{
    foreach ($array as $key => $value) {
        if (is_array($value))
            $value = removeEmptyElements($value);

        if (empty($value) && false !== $value && 0 !== $value)
            unset($array[$key]);
        else
            $array[$key] = $value;
    }

    return $array;
}

print_r(removeEmptyElements($test));