PHP - Add level to multidimensional array

Question

I have an multidimensional array and I want to add a key and value to every array within the multidimensional array. The value has to be the level of how deep the array is within the multidimensional array.

For example:

Array(
    [0] Array
        (
            [id] 1
            [parentid] null
            [0] Array
                (
                    [id] 101
                    [parentid] 1
    [1] Array
        (
            [id] 2
            [parentid] null
            [0] Array
                (
                    [id] 161
                    [parentid] 2
                    [children] Array
                        (
                            [0] Array
                                (
                                    [id] 300
                                    [parentid] 161
                                 )

Expected output:

Array(
    [0] Array
        (
            [id] 1
            [parentid] null
            [level] 1
            [0] Array
                (
                    [id] 101
                    [parentid] 1
                    [level] 2
    [1] Array
        (
            [id] 2
            [parentid] null
            [level] 1
            [0] Array
                (
                    [id] 161
                    [parentid] 2
                    [level] 2
                    [children] Array
                        (
                            [0] Array
                                (
                                    [id] 300
                                    [parentid] 161
                                    [level] 3
                                 )

What have you tried to get this done? It should not be that difficult — Nico Haase
– Nico Haase, Commented Apr 3, 2018 at 8:43
You can check there :- stackoverflow.com/questions/8587341/… — Nageen
– Nageen, Commented Apr 3, 2018 at 8:57

Tschallacka · Accepted Answer · 2018-04-03 19:41:23Z

2

You basically want to use a recursive function that works with a reference to an array.

By using a parameter &$foo with the & in front of it, you're designating it as a reference to that object.

In the case of an array it will not make a copy of the modification, but perform the modification on the original passed array.

EDIT added suggestion of Yoshi in the comments to pass &value as reference too.

See it live: https://ideone.com/NhKABF

<?php
$array = [
    'hello' => 'world',
    'doing' => [
        'hello' => 'universe',
        'going' => [
            'hello' => 'existence'
         ],
        'moving' => [
            'answer' => 42,
        ]
    ]
];
function levelUp(&$array, $level = 1) 
//               ^-- See that one? that's the  magic.
{
    $array['level'] = $level;

    foreach($array as $key => &$value) {
    //                        ^-- important to add that & here too
        if(is_array($value)) {
            levelUp($value, $level + 1);
        }
    }
}
levelUp($array);
var_dump($array);

edited Apr 3, 2018 at 19:41

answered Apr 3, 2018 at 12:12

Tschallacka

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2 Comments

Mulan Over a year ago

Small thing: I think the OP wants the level field set to the data's nesting level, not the id field. Otherwise great answer.

Umar Farooque Khan Over a year ago

@Nibboro is given solution solved your problem

Nageen · Accepted Answer · 2018-04-03 08:58:48Z

0

function buildTree(array $elements, $parentId = 0) {
$branch = array();

foreach ($elements as $element) {
    if ($element['parent_id'] == $parentId) {
        $children = buildTree($elements, $element['id']);
        if ($children) {
            $element['children'] = $children;
        }
        $branch[] = $element;
    }
}

return $branch;

}

$tree = buildTree($rows);

answered Apr 3, 2018 at 8:58

Nageen

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8 Comments

Nageen Over a year ago

I think it will help you.

Nico Haase Over a year ago

Obviously, because otherwise you wouldn't have posted it ;)

Nibboro Over a year ago

I use this function to build my tree structure. But I've no idea how to add the current level of the array to the array.

Nageen Over a year ago

Have you store level in DB??

Nibboro Over a year ago

No, the level is not stored in the database yet. Im trying to add the level in the array and want to use that array to insert the data in the database.

|

Ramy Herrira · Accepted Answer · 2018-04-03 09:15:39Z

0

I don't know if it's relevant but why not use a library like BlueM/Tree ?
It has features built for this kind of problems.

// Get a node's ID
$id = $node->getId();

// Get the node's hierarchical level (1-based)
$level = $node->getLevel();

edited Apr 3, 2018 at 9:15

answered Apr 3, 2018 at 9:02

Ramy Herrira

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1 Comment

Nageen Over a year ago

May be but i have not use yet that library.

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