PHP un-nest all element in multidimensional array

Question

I have a multidimensional array in PHP and I want to un-nest all elements to bring them to the top level. Here is the array:

Array
(
    [0] => Array
        (
            [id] => 1
            [color] => red

        )

    [1] => Array
        (
            [0] => Array
                (
                    [id] => 2
                    [color] => blue
                )

            [1] => Array
                (
                    [0] => Array
                        (
                            [id] => 3
                            [color] => green
                        )

                )

            [2] => Array
                (
                    [id] => 4
                    [color] => blue
                )

        )

    [2] => Array
        (
            [id] => 5
            [color] => purple
        )

)

What I want end the end is this... so basically it loops over the array and any group it just unnests it. Sorry, I don't know the proper terminology. Is there PHP function for this? I've tried several solutions on stack but it moves all key values pairs up to the top and not just the array groups --- it just creates a mess.

(
    [0] => Array
        (
            [id] => 1
            [id] => red                
        )
    [1] => Array
        (
            [id] => 2
            [color] => blue
        )

    [2] => Array
        (
            [id] => 3
            [color] => green
        )

    [3] => Array
        (
            [id] => 4
            [color] => blue
        )


    [4] => Array
        (
            [id] => 5
            [color] => purple
        )

)

Thanks!

score 0 · Answer 1 · answered Sep 17 '19 at 01:57

You can do it like this, check the Demo

$result = [];
array_walk_recursive($array,function(&$v)use($result){
   $result[] = $v;
});
$result = array_chunk($result,2);
$result = array_map(function($v){return array("id"=>$v[0],"color"=>$v[1]);});
print_r($result);

score 0 · Answer 2 · answered Sep 17 '19 at 07:25

0

You can unpack it by using array_walk_recursive

$i = 0;
array_walk_recursive($a, function($v,$k)use(&$r,&$i){
  $r[$i][$k] = $v;
  ($k == 'color') ? $i++ :$i; 
});
print_r($r);

Working example :- https://3v4l.org/YPT2M

answered Sep 17 '19 at 07:25

Rakesh Jakhar

6,380
2
11
20

Rahul · Answer 3 · 2019-09-17T14:09:44.860

Use simple generic recursion as below(no id, no color),

function flattenArray($arr = [])
{
    $retArr = [];
    foreach ($arr as $val) {
        if (is_array($val)) {
            $retArr[] = array_filter($val, function ($v) {
                return !is_array($v);
            });
            $retArr = array_merge(array_filter($retArr), flattenArray($val));
        }
    }
    return $retArr;
}
$arr = flattenArray($arr);

Demo

Output:-

Array
(
    [0] => Array
        (
            [id] => 1
            [color] => red
        )

    [1] => Array
        (
            [id] => 2
            [color] => blue
        )

    [2] => Array
        (
            [id] => 3
            [color] => green
        )

    [3] => Array
        (
            [id] => 4
            [color] => blue
        )

    [4] => Array
        (
            [id] => 5
            [color] => purple
        )

)

PHP un-nest all element in multidimensional array

3 Answers3