计算嵌套数组树中的叶子数

Question

我有一个嵌套的数组树，它是由具有以下功能的平面数组生成的：

function convertToTree(array $flat, $idField = 'id',
                        $parentIdField = 'parentId',
                        $childNodesField = 'childNodes') {
    $indexed = array();
    // first pass - get the array indexed by the primary id  
    foreach ($flat as $row) {
        $indexed[$row[$idField]] = $row;
        $indexed[$row[$idField]][$childNodesField] = array();
    }

    //second pass  
    $root = null;
    foreach ($indexed as $id => $row) {
        $indexed[$row[$parentIdField]][$childNodesField][$id] =& $indexed[$id];
        if (!$row[$parentIdField]) {
            $root = $id;
        }

    }
    return array($root => $indexed[$root]);
}

我需要为数组的每个节点添加一个条目“ NUMBER OF LEAVES”。该条目应计算该节点所有子节点的所有叶子：

Array ( 
    [9] => Array ( 
        [id] => 9, 
        [parentId] => null,
        [name] => Item 0, 
        [NUMBER OF LEAVES] => 4,  (corresponding to leaves 100 and 101 + 200 and 201)
        [childNodes] => Array 
            ( 
                [1] => Array ( 
                    [id] => 1, 
                    [parentId] => 9, 
                    [name] => Item 1, 
                    [NUMBER OF LEAVES] => 2,   (corresponding to leaves 100 and 101)
                    [childNodes] => Array ( 
                        [10] => Array ( 
                            [id] => 10, 
                            [parentId] => 1, 
                            [name] => Item 10, 
                            [childNodes] => Array ( 
                                [100] => Array ( 
                                    [id] => 100, 
                                    [parentId] => 10, 
                                    [name] => Item 100, 
                                    [childNodes] => Array ( ) 
                                ) 
                                [101] => Array ( 
                                    [id] => 101, 
                                    [parentId] => 10, 
                                    [name] => Item 101, 
                                    [childNodes] => Array ( ) 
                                ) 
                            ) 
                        ) 
                    ) 
                ) 
                [2] => Array ( 
                    [id] => 2, 
                    [parentId] => 9, 
                    [name] => Item 2, 
                    [NUMBER OF LEAVES] => 2,   (corresponding to leaves 200 and 201)
                    [childNodes] => Array ( 
                        [20] => Array ( 
                            [id] => 20, 
                            [parentId] => 2, 
                            [name] => Item 20, 
                            [childNodes] => Array ( 
                                [200] => Array ( 
                                    [id] => 200, 
                                    [parentId] => 20, 
                                    [name] => Item 200, 
                                    [childNodes] => Array ( ) 
                                ) 
                                [201] => Array ( 
                                    [id] => 201, 
                                    [parentId] => 20, 
                                    [name] => Item 201, 
                                    [childNodes] => Array ( ) 
                                ) 
                            ) 
                        ) 
                    ) 
                ) 
            ) 
    ) 
)

Answer 1

这可以解决您阵列中每个节点的“ NUMBER OF LEAVES”问题。该条目应计入该节点所有子节点的所有叶子”

它来自php 手册 $ food = array（'fruits'=> array（'orange'，'banana'，'apple'），'veggie'=> array（'carrot'，'collard'，'pea'）） ;

     // recursive count
     echo count($food, COUNT_RECURSIVE); // output 8

     // normal count
     echo count($food); // output 2`

Answer 2

您可以轻松地做到这一点：

$leaves = 0;
array_walk_recursive($yourArray, function ($leaves) use (&$leaves) {
  $leaves++;
});

例子 ：

$foods = array(
  'fruits' => array('orange', 'banana', 'apple'),
  'veggie' => array('carrot', 'collard', 'pea')
);

$leaves = 0;
array_walk_recursive($foods, function ($leaves) use (&$leaves) {
  $leaves++;
});
echo $leaves; // will output 6