PHP - Loop through nested array and increase foreach

Question

I have a huge JSON array which has categories, sub categories, sub-sub categories etc.

It could continue to grow in future without my control so wondering how best to continue to go through each category and their ['children'] elements until no results found.

My approach so far is surely too basic? Wondering what would be a better approach ideally.

foreach( $json['results'] as $parent_cat ) {
// var_dump($parent_cat['path']);

foreach( $parent_cat['children'] as $sub_cat ) {
  // var_dump($sub_cat['path']);

  foreach( $sub_cat['children'] as $sub_sub_cat ) {
    // var_dump($sub_sub_cat['path']);

    foreach( $sub_sub_cat['children'] as $sub_sub_sub_cat) {
      // var_dump($sub_sub_sub_cat['path']);

      foreach( $sub_sub_sub_cat['children'] as $sub_sub_sub_sub_cat) {
        // var_dump($sub_sub_sub_sub_cat['path']);

        foreach( $sub_sub_sub_sub_cat['children'] as $sub_sub_sub_sub_sub_cat) {
          // var_dump($sub_sub_sub_sub_sub_cat['path']);

          foreach( $sub_sub_sub_sub_sub_cat['children'] as $sub_sub_sub_sub_sub_sub_cat) {
            // var_dump($sub_sub_sub_sub_sub_sub_cat['path']);

            foreach( $sub_sub_sub_sub_sub_cat['children'] as $sub_sub_sub_sub_sub_sub_cat) {
              var_dump($sub_sub_sub_sub_sub_sub_cat['path']);
            }
          }
        }
      }
    }
  }
}

}

seems like a job for [recursion](https://en.wikipedia.org/wiki/Recursion_(computer_science)) — Nick Parsons, Jul 05 '19 at 13:39
Possible duplicate of [How does RecursiveIteratorIterator work in PHP?](https://stackoverflow.com/questions/12077177/how-does-recursiveiteratoriterator-work-in-php) — Darragh Enright, Jul 05 '19 at 13:43
Have a look into recursive iterators in PHP, the link above should provide you with some useful info. — Darragh Enright, Jul 05 '19 at 13:44
What does the array look like and what is the expected result/output? — Andreas, Jul 05 '19 at 13:48
What's the objective of looping so deeply? All I can see is a var_dump(). — nice_dev, Jul 05 '19 at 15:19

score 1 · Answer 1 · answered Jul 05 '19 at 13:44

1

instead of all this hassle just use array_walk_recursive if you want to fetch path,

array_walk_recursive($arr, function($v,$k) use(&$r){
    if($k == 'path'){
        $r[] = $v;
    }
});
print_r($r);

answered Jul 05 '19 at 13:44

Rahul

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score 1 · Answer 2 · answered Jul 05 '19 at 14:07

Recursion is a typical approach to work with nested data.

<?php

class ResultsDumper {
    public function dumpRecursive( array $parent_cat ) {
        var_dump( $parent_cat['path'] );

        if ( isset( $parent_cat['children'] ) ) {
            foreach ( $parent_cat['children'] as $sub_cat ) {
                // Notice how this function is calling itself
                $this->dumpRecursive( $sub_cat );
            }
        }
    }
}

$resultsDumper = new ResultsDumper();
$resultsDumper->dumpRecursive( $json['results'] );

PHP - Loop through nested array and increase foreach

2 Answers2