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PHP – Multidimensional array to single dimensional array

I have been trying to convert my Multidimensional array to single-dimensional array. I have tried with PHP array in-built functions, but not able to get required output.

Problem
I have Multidimensional array for categories hierarchy, that stores child category in ‘children’ key. there is no limit for children level, it could be any number.

Result
I am trying to convert this Multidimensional array to single dimensional array, but children array should be added just after their parent with having extra key ‘level’ to display hierarchy order.

Multidimensional array




$arr = [
    [
        "id" => 1495,
        "title" => "Acoustics",
        "slug" => "acoustics",
        "children" => [
            [
                "id" => 50127,
                "title" => "Acoustic Lighting",
                "slug" => "acoustic-lighting",
                "children" => [
                    [
                        "id" => 50131,
                        "title" => "Acoustic Pendant Lighting",
                        "slug" => "acoustic-pendant-lighting",
                        "children" => [],
                    ],
                ],
            ],
            [
                "id" => 57168,
                "title" => "Acoustic Plaster Systems",
                "slug" => "acoustic-plaster-systems",
                "children" => [],
            ],
        ],
    ],
    [
        "id" => 50182,
        "title" => "Architecture",
        "slug" => "architecture",
        "children" => [
            [
                "id" => 1488,
                "title" => "Ceilings",
                "slug" => "ceilings",
                "children" => [
                    [
                        "id" => 50205,
                        "title" => "Suspended Ceiling Systems",
                        "slug" => "suspended-ceiling-systems",
                        "children" => [
                            [
                                "id" => 56299,
                                "title" => "Baffles",
                                "slug" => "baffles",
                                "children" => [],
                            ],
                        ],
                    ],
                ],
            ],
            [
                "id" => 50187,
                "title" => "Doors",
                "slug" => "doors",
                "children" => [
                    [
                        "id" => 50188,
                        "title" => "Single Leaf",
                        "slug" => "single-leaf",
                        "children" => [],
                    ],
                ],
            ],
        ],
    ],
    [
        "id" => 43859,
        "title" => "Decor",
        "slug" => "decor",
        "children" => [
            [
                "id" => 50137,
                "title" => "Art and Prints",
                "slug" => "art-and-prints",
                "children" => [],
            ],
            [
                "id" => 54014,
                "title" => "Planters",
                "slug" => "planters",
                "children" => [],
            ],
            [
                "id" => 50138,
                "title" => "Sculptures and Objects",
                "slug" => "sculptures-and-objects",
                "children" => [],
            ],
            [
                "id" => 43860,
                "title" => "Wall / Ceiling Decor",
                "slug" => "wall-ceiling-decor",
                "children" => [
                    [
                        "id" => 43861,
                        "title" => "Green Walls",
                        "slug" => "green-walls",
                        "children" => [],
                    ],
                    [
                        "id" => 50139,
                        "title" => "Wall Paper & Wall Coverings",
                        "slug" => "wall-paper-wall-coverings",
                        "children" => [],
                    ],
                ],
            ],
        ],
    ],
];

Single dimensional array, I am trying to get


Array
(
    [0] => Array
        (
            [id] => 1495
            [title] => Acoustics
            [slug] => acoustics
            [level] => 0
        )

    [1] => Array
        (
            [id] => 50127
            [title] => Acoustic Lighting
            [slug] => acoustic-lighting
            [level] => 1
        )

    [2] => Array
        (
            [id] => 50131
            [title] => Acoustic Pendant Lighting
            [slug] => acoustic-pendant-lighting
            [level] => 2
        )

    [3] => Array
        (
            [id] => 57168
            [title] => Acoustic Plaster Systems
            [slug] => acoustic-plaster-systems
            [level] => 1
        )

    [4] => Array
        (
            [id] => 50182
            [title] => Architecture
            [slug] => architecture
            [level] => 0
        )

    [5] => Array
        (
            [id] => 1488
            [title] => Ceilings
            [slug] => ceilings
            [level] => 1
        )

    [6] => Array
        (
            [id] => 50205
            [title] => Suspended Ceiling Systems
            [slug] => suspended-ceiling-systems
            [level] => 2
        )

    [7] => Array
        (
            [id] => 56299
            [title] => Baffles
            [slug] => baffles
            [level] => 3
        )

    [8] => Array
        (
            [id] => 50187
            [title] => Doors
            [slug] => doors
            [level] => 1
        )

    [9] => Array
        (
            [id] => 50188
            [title] => Single Leaf
            [slug] => single-leaf
            [level] => 2
        )

    [10] => Array
        (
            [id] => 43859
            [title] => Decor
            [slug] => decor
            [level] => 0
        )

    [11] => Array
        (
            [id] => 50137
            [title] => Art and Prints
            [slug] => art-and-prints
            [level] => 1
        )

    [12] => Array
        (
            [id] => 54014
            [title] => Planters
            [slug] => planters
            [level] => 1
        )

    [13] => Array
        (
            [id] => 50138
            [title] => Sculptures and Objects
            [slug] => sculptures-and-objects
            [level] = 1
        )

    [14] => Array
        (
            [id] => 43860
            [title] => Wall / Ceiling Decor
            [slug] => wall-ceiling-decor
            [level] => 1
        )

    [15] => Array
        (
            [id] => 43861
            [title] => Green Walls
            [slug] => green-walls
            [level] => 2
        )

    [16] => Array
        (
            [id] => 50139
            [title] => Wall Paper & Wall Coverings
            [slug] => wall-paper-wall-coverings
            [level] => 2
        )

)

Here what I have tried,

function array_flatten( $arr, $out=array() )  {
    foreach( $arr as $key => $item ) {
        if ( is_array( $item )  ) {
            $out = array_merge( $out, array_flatten( $item ) );
        } else {
            $out[] = $item;
        }
    }
    return $out;
}

$result_single = array_flatten($arr);
$result_arr = array_chunk($result_single, 3);
echo "<pre>"; print_r($result_arr); echo "</pre>";
Tags:

2

Answers


  1. 0

    you need to use recursion

    function flattenArray($array, $level = 0, &$result = []) {
    foreach ($array as $element) {
        // Copy the element and add the level key to it
        $flattenedElement = $element;
        $flattenedElement['level'] = $level;
        unset($flattenedElement['children']); // Remove children key

        // Add the flattened element to the result array
        $result[] = $flattenedElement;

        // If there are children, recursively flatten them
        if (!empty($element['children'])) {
            flattenArray($element['children'], $level + 1, $result);
        }
    }

    return $result;
}

// Your multidimensional array
$arr = [
    // ... your array structure ...
];

// Flatten the array
$flattenedArray = flattenArray($arr);

// Print the result
print_r($flattenedArray);
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  2. 0

    You could do this by using a stack:

    // set up result array
$output = [];

// initialise our stack, add 'level' => 0 to all top level nodes
$todo = array_map(fn($n) => $n + ['level' => 0], $arr);

while ($node = array_shift($todo)) {

    // add 'level' => <parent level + 1> to all child nodes
    $childNodes = array_map(fn($n) => $n + ['level' => $node['level'] + 1], $node['children']);

    // don't include the 'children' element in the output
    unset($node['children']);

    // add node to the result array
    $output[] = $node;

    // put child nodes on the top of the stack, so we process them next
    array_unshift($todo, ...$childNodes);
}

print_r($output);
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