如何建立从列表多维数组？ [英] How to create multi-dimensional array from a list?

问题描述

我有父ID类别在MySQL中的列表。如何创建从列表中选择PHP数组。

I have a list of categories in MySQL with parent ID. How can I create a PHP array from the list.

ID  Category      Parent_ID
1   Car           NULL
2   Education     NULL
3   Mathematics   2
4   Physics       2
5   Astrophysics  4

我要产生这种结构的阵列

I want to produce an array of this structure

array(
    "Car" => "1",
    "Education" => array("Mathematics" => "2", "Physics" => array("Astrophysics" => "4"))
);

由于事实上，键/值并不重要，因为我将与其他栏目工作了。我只是想知道如何扫描列表中，并产生多级列表。

As a matter of fact, key/value is not important as I will work with other columns too. I just want to know how to scan the list and produce multi-level list.

推荐答案

一些非常简单的递归构建树结构：

Some very simple recursion to build a tree structure:

function buildTree(array $data, $parent = null) {
    $branch = array();

    foreach ($data as $row) {
        if ($row['parent_id'] == $parent) {
            $row['children'] = buildTree($data, $row['id']);
            $branch[] = $row;
        }
    }

    return $branch;
}

$tree = buildTree($rowsFromDatabase);

有一个明确的'孩子'键通常是preferable给你提出的结构，但随时根据需要修改。

Having an explicit 'children' key is usually preferable to the structure you're proposing, but feel free to modify as needed.

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