PHP多维数组w/父ID到类别分类数组，Ebay风格

Question

几天后准备辞职。我给eBay的交易API打了个电话，以返回一个类别列表。下面的数组显示了如何从API返回这些类别。我正拼命地把它整理成一个分类法，就像下面的第一个灰色盒子。

请注意，每行开头的数字是该特定行的最后类别的id。

3270: Vehicle Electronics & GPS
175716: Vehicle Electronics & GPS > Car Audio
18805: Vehicle Electronics & GPS > Car Audio > Car Subwoofers
18795: Vehicle Electronics & GPS > Car Audio > Car Amplifiers
39754: Vehicle Electronics & GPS > Car Audio > Car Audio In-Dash Units

我把这个数组大大缩短为一个例子。为了构建分类法，许多类别都将被注入进来。

CategoryLevel可以从任意数开始，也可以以任意数结束。在本例中，它从2开始，最高级别为4。

Array
(
    [3270] => Array
        (
            [CategoryID] => 3270
            [CategoryLevel] => 2
            [CategoryName] => Vehicle Electronics & GPS
            [CategoryParentID] => 293
        )

    [175716] => Array
        (
            [CategoryID] => 175716
            [CategoryLevel] => 3
            [CategoryName] => Car Audio
            [CategoryParentID] => 3270
        )


    [79839] => Array
        (
            [CategoryID] => 79839
            [CategoryLevel] => 4
            [CategoryName] => Signal Processors
            [CategoryParentID] => 175716
            [LeafCategory] => true
        )

    [18805] => Array
        (
            [CategoryID] => 18805
            [CategoryLevel] => 4
            [CategoryName] => Car Subwoofers
            [CategoryParentID] => 175716
            [LeafCategory] => true
        )

    [18795] => Array
        (
            [CategoryID] => 18795
            [CategoryLevel] => 4
            [CategoryName] => Car Amplifiers
            [CategoryParentID] => 175716
            [LeafCategory] => true
        )

    [39754] => Array
        (
            [CategoryID] => 39754
            [CategoryLevel] => 4
            [CategoryName] => Car Audio In-Dash Units
            [CategoryParentID] => 175716
            [LeafCategory] => true
        )


)

提前感谢您的帮助！

Answer 1

编辑:再次，修正错误。

<?php
require_once("samplearray.php");

function makeNestedData($data){
    //create a nested tree using the above structure
    $nested = array();

    //loop over each category
    foreach($data as &$category){
        //is there is no children array, add it
        if(!isset($category['Children'])){
            $category['Children'] = array();
        }
        //check if there is a matching parent
        if(isset($data[$category['CategoryParentID']])){
            //add this under the parent as a child by reference
            if(!isset($data[$category['CategoryParentID']]['Children'])){
                $data[$category['CategoryParentID']]['Children'] = array();
            }
            $data[$category['CategoryParentID']]['Children'][$category['CategoryID']] = &$category;
        //else, no parent found, add at top level
        } else {
            $nested[$category['CategoryID']] = &$category;
        }
    }
    unset($category);
    return $nested;
}

//now flatten out the nested array recursively
function flattenNested($nested, $parent=''){
    $out = array();
    foreach($nested as $category){
        $categoryName = $parent.$category['CategoryName'];
        $out[$category['CategoryID']] = $categoryName;
        //recurse for each child
        $out += flattenNested($category['Children'], $categoryName.' > ');
    }
    return $out;
}

$result = flattenNested(makeNestedData($array));
print_r($result);

产出：

Array
(
    [3270] => Vehicle Electronics & GPS
    [175716] => Vehicle Electronics & GPS > Car Audio
    [79839] => Vehicle Electronics & GPS > Car Audio > Signal Processors
    [18805] => Vehicle Electronics & GPS > Car Audio > Car Subwoofers
    [18795] => Vehicle Electronics & GPS > Car Audio > Car Amplifiers
    [39754] => Vehicle Electronics & GPS > Car Audio > Car Audio In-Dash Units
)

输出是一个数组，其右侧类别id为键，值为带有类别文本的字符串。

这似乎是一种复杂或不必要的方法，但这确实是更好的方法之一-- IMO，因为它将处理所有类别和嵌套级别的任何顺序。唯一的限制将与递归和可能的内存有关，但我尝试在可能的情况下使用引用，以尽可能减少内存占用。

示例：http://codepad.viper-7.com/Fke5OA