php中计算树状结构数据中的合计

前言

在项目开发的过程中有时候遇到树状结构数据计算从最末级节点依次计算到根节点中所有数据值的和，也就是计算子级节点数据相加等于父级节点，以此类推到根节点。
下面的方法使用到了递归查询计算的方法。
树状结构数据示例：

$tree = [
    0 => [
        "Code" => "1",
        "PCode" => "",
        "num" => 1,
        "Price" => 2,
        "children" => [
            0 => [
                "Code" => "1.1",
                "PCode" => "1",
                "num" => 1,
                "Price" => 3,
            ],
            1 => [
                "Code" => "1.2",
                "PCode" => "1",
                "num" => 1,
                "Price" => 4,
            ],
        ],
    ],
    1 => [
        "Code" => "2",
        "PCode" => "",
        "num" => 1,
        "Price" => 2,
        "children" => [
            0 => [
                "Code" => "2.1",
                "PCode" => "2",
                "num" => 1,
                "Price" => 3,
            ],
            1 => [
                "Code" => "2.2",
                "PCode" => "2",
                "num" => 1,
                "Price" => 3,
                "children" => [
                    0 => [
                        "Code" => "2.2.1",
                        "PCode" => "2.2",
                        "num" => 1,
                        "Price" => 3,
                    ],
                ],
            ],
        ],
    ],
];

这里计算节点的合价=单价*数量

function sum($data)
{
    
    $aaa = 0;
    foreach ($data as $item) {
    
        if (isset($item['children']) && count($item['children']) > 0) {
    
            $item['TotalPrice'] = sum($item['children']); //合计
        } else {
    
            $item['TotalPrice'] = $item['num'] * $item['Price']; //合价
        }
        $aaa += $item['TotalPrice'];
    }
    return $aaa;
}

对方法进行调用

$a = sum($tree);
print_r($a);//例子数据中的合计为13