在PHP中的多维数组中搜索过滤器

Question

How would I create a search function that search in multidimensional nested array?

Given the following array :

Array
(
[0] => Array
    (
        [id] => 1
        [parent_name] => ACTIVITIES
        [children] => Array
            (
            )

    )

[1] => Array
    (
        [id] => 2
        [parent_name] => ANIMALS/PETS
        [children] => Array
            (
            )

    )

[2] => Array
    (
        [id] => 3
        [parent_name] => ART
        [children] => Array
            (
                [0] => Array
                    (
                        [post_id] => 100
                        [child_name] => Bookeeping
                        [painting] => Array
                            (
                                [0] => flower
                                [1] => beach
                                [2] => sunrise
                            )

                    )

                [1] => Array
                    (
                        [post_id] => 101
                        [child_name] => Addiction
                        [painting] => Array
                            (
                                [0] => sunrise
                                [1] => beach
                            )

                    )

            )

    )
[3] => Array
    (
        [id] => 4
        [parent_name] => Music
        [children] => Array
            (
                [0] => Array
                    (
                        [post_id] => 102
                        [child_name] => POP
                        [painting] => Array
                            (
                                [0] => suntown
                                [1] => beachfull
                                [2] => sunrise
                            )

                    )

                [1] => Array
                    (
                        [post_id] => 103
                        [child_name] => Rock
                        [painting] => Array
                            (
                                [0] => sunrisenew
                                [1] => beachnew
                            )

                    )

            )

    )
)

How would I filter this array with a key which search in 'painting'?

For example search key is "sun"

Result should be like this :

Array
(

[2] => Array
    (
        [id] => 3
        [parent_name] => ART
        [children] => Array
            (
                [0] => Array
                    (
                        [post_id] => 100
                        [child_name] => Bookeeping
                        [painting] => Array
                            (
                                [2] => sunrise
                            )

                    )

                [1] => Array
                    (
                        [post_id] => 101
                        [child_name] => Addiction
                        [painting] => Array
                            (
                                [0] => sunrise
                            )

                    )

            )

    )
[3] => Array
    (
        [id] => 4
        [parent_name] => Music
        [children] => Array
            (
                [0] => Array
                    (
                        [post_id] => 102
                        [child_name] => POP
                        [painting] => Array
                            (
                                [0] => suntown
                            )

                    )

                [1] => Array
                    (
                        [post_id] => 103
                        [child_name] => Rock
                        [painting] => Array
                            (
                                [0] => sunrisenew
                            )

                    )

            )

    )
)

Answer 1

$needle = "sun";
$filteredArr = array_filter(
    $arr,
    function($v) use ($needle) {
        foreach($v['children'] as $child) {
            // "Version 1" of filtering, no "parts of strings" searches
            if (in_array($needle, $child['painting'])) {
                return true;
            }

            // "Version 2" of filtering, keyword may be part of a painting string
            foreach($child['painting'] as $painting) {
                if (strpos($painting, $needle) !== false) {
                    return true;
                }
            }
        }

        return false;
    }
);

If you use the callback for array_filter() then you can do fairly advanced filterings.

Edit New version of answer for removing the entries in painting arrays not matching the pattern.

This works by doing nested foreach loops, all the way in to the innermost array needed, painting in this case. The painting array is filtered so that all non matching elements in it are removed. When done with this, at the next level outwards, the painting array is checked, and if empty the removal kind of "propagates outwards". This way only the entries with matching painting entries should be left, and it should be sort of scalable.

The references aren't strictly necessary, one could add array key variables to the foreach loops instead. But I didn't like all the indexing this caused.

$needle = 'sun';

foreach($arr as $entryKey => &$entry) {
    foreach($entry['children'] as $childKey => &$child) {
        foreach($child['painting'] as $paintingKey => $painting) {
            if (strpos($painting, $needle) === false) {
                unset($child['painting'][$paintingKey]);
            }
        }

        if (empty($child['painting'])) {
            unset($entry['children'][$childKey]);
        }
    }

    if (empty($entry['children'])) {
        unset($arr[$entryKey]);
    }
}
unset($entry, $child); // Take no risks with references