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  1. <?php
  2. $array = [
  3.   ['level'=>1, 'name' => 'Root #1'],
  4.   ['level'=>1, 'name' => 'Root #2'],
  5.   ['level'=>2, 'name' => 'subroot 2-1'],
  6.   ['level'=>3, 'name' => '__subroot 2-1/1'],
  7.   ['level'=>2, 'name' => 'subroot 2-2'],
  8.   ['level'=>1, 'name' => 'Root #3']
  9. ];
  10.  
  11. function buildTree(array &$nodes) {
  12.         $activeNodes = [];
  13.  
  14.         foreach ($nodes as $index => &$node) {
  15.                 $node['children'] = [];
  16.                 $level = $node['level'];
  17.                 $activeNodes[$level] = &$node;
  18.  
  19.                 if ($level > 1) {
  20.                         $activeNodes[$level - 1]['children'][] = &$node;
  21.                         unset($nodes[$index]);
  22.                 }
  23.         }
  24. }
  25.  
  26. buildTree($array);
  27. echo '<pre>';
  28. var_dump($array);
Success #stdin #stdout 0.01s 20520KB
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Standard input is empty
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<pre>array(3) {
  [0]=>
  array(3) {
    ["level"]=>
    int(1)
    ["name"]=>
    string(7) "Root #1"
    ["children"]=>
    array(0) {
    }
  }
  [1]=>
  array(3) {
    ["level"]=>
    int(1)
    ["name"]=>
    string(7) "Root #2"
    ["children"]=>
    array(2) {
      [0]=>
      array(3) {
        ["level"]=>
        int(2)
        ["name"]=>
        string(11) "subroot 2-1"
        ["children"]=>
        array(1) {
          [0]=>
          array(3) {
            ["level"]=>
            int(3)
            ["name"]=>
            string(15) "__subroot 2-1/1"
            ["children"]=>
            array(0) {
            }
          }
        }
      }
      [1]=>
      array(3) {
        ["level"]=>
        int(2)
        ["name"]=>
        string(11) "subroot 2-2"
        ["children"]=>
        array(0) {
        }
      }
    }
  }
  [5]=>
  array(3) {
    ["level"]=>
    int(1)
    ["name"]=>
    string(7) "Root #3"
    ["children"]=>
    array(0) {
    }
  }
}
https://ideone.com/cXFAYl
language:
PHP (php 7.3.5)
created:
11 years ago
visibility:
secret

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