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<?php $array = array( 55 => array( 'ident' => 'test 1', 'depth' => 1, ), 77 => array( 'parent_id' => 55, 'ident' => 'test 2', 'depth' => 2, ), 109 => array( 'parent_id' => 77, 'ident' => 'test 3', 'depth' => 3, ), 78 => array( 'parent_id' => 55, 'ident' => 'test 4', 'depth' => 2, ), 25 => array( 'ident' => 'test 5', 'depth' => 1, ) ); function v1($array) { foreach ($array as $key => &$sub) { if (isset($sub['parent_id'])) { $array[$sub['parent_id']]['children'][$key] = &$sub; } } unset($sub); // unset the reference to make sure to not overwrite it later... // now remove the entries with parents foreach ($array as $key => $sub) { if (isset($sub['parent_id'])) unset($array[$key]); } return $array; } function &find_by_key($key, $array) { foreach($array as $k => &$v) { if($key == $k) { return $v; } } foreach($array as $sub) { if(isset($sub['children']) && FALSE !== ($found = &find_by_key($key, $sub['children']))) { return $found; } } return FALSE; } function v2($array) { $out = array(); foreach ($array as $key => $sub) { if(!isset($sub['parent_id'])) { $out[$key] = $sub; } else { $parent = &find_by_key($sub['parent_id'], $out); $parent['children'][$key] = $sub; } var_dump($out); } return $out; } //var_dump(v1($array)); var_dump(v2($array));
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.12 - 7.3.31, 7.4.0 - 7.4.25, 7.4.27 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } Notice: Only variable references should be returned by reference in /in/rnCrM on line 59 array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } }
Output for 7.3.32 - 7.3.33, 7.4.26
array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } }
Output for 5.0.0 - 5.0.5
array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } Strict Standards: Only variable references should be returned by reference in /in/rnCrM on line 59 array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(1) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } } array(2) { [55]=> array(2) { ["ident"]=> string(6) "test 1" ["depth"]=> int(1) } [25]=> array(2) { ["ident"]=> string(6) "test 5" ["depth"]=> int(1) } }
Output for 4.4.2 - 4.4.9
Parse error: syntax error, unexpected '&', expecting T_VARIABLE or '$' in /in/rnCrM on line 30
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1
Parse error: parse error, unexpected '&', expecting T_VARIABLE or '$' in /in/rnCrM on line 30
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error, expecting `T_VARIABLE' or `'$'' in /in/rnCrM on line 30
Process exited with code 255.

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