從XML數據集中使用PHP創建嵌套列表

Question

我試圖從包含類別和子類別+圖像的現有XML文件構建無序列表。我需要每個子類別都是無序列表中的項目，每個相關圖像都嵌套在列表中。子類別只應顯示一次（如果相同，則不得重複）。我相信我正在尋找的是一個遞歸循環，但那就是我迷失的地方。

從本質上講，我想實現一個類似的外觀：

-------------- DOGS -------------
[..........小..........]
[圖片] [圖片]
[..........大... .......]
[圖片]
-------------- CATS -------------
[.... ......中..........]
[圖片]
[..........大..........]
[圖片] [圖片]

我的XML文件的結構：

<root> 
    <animal> 
     <category>DOGS</category> 
     <subcategory>small</subcategory> 
     <name>Terrier</name> 
     <image>aaa.jpg</image> 
    </animal> 
    <animal> 
     <category>-</category> 
     <subcategory>small</subcategory> 
     <name>Havanese</name> 
     <image>bbb.jpg</image> 
    </animal> 
    <animal> 
     <category>-</category> 
     <subcategory>large</subcategory> 
     <name>Dalmatian</name> 
     <image>ccc.jpg</image> 
    </animal> 
    <animal> 
     <category>CATS</category> 
     <subcategory>medium</subcategory> 
     <name>Abyssinian</name> 
     <image>ddd.jpg</image> 
    </animal> 
    <animal> 
     <category>-</category> 
     <subcategory>large</subcategory> 
     <name>Birman</name> 
     <image>eee.jpg</image> 
    </animal> 
    <animal> 
     <category>-</category> 
     <subcategory>large</subcategory> 
     <name>American Shorthair</name> 
     <image>fff.jpg</image> 
    </animal> 
</root> 

這是我迄今爲止嘗試：

<?php 

    $xml = simplexml_load_file("file.xml"); 

    $categories  = array(); 
    $subcategories = array(); 
    $names  = array(); 
    $image   = array(); 

    foreach($xml->animal as $animals) { 
     $category  = $animals->category; 
     $subcategory  = $animals->subcategory; 
     $name   = $animals->name; 
     $image  = $animals->image; 

     $categories[]  = $category; 
     $subcategories[] = $subcategory; 
     $names[]   = $name; 
     $images[]  = $image 
    } 

    function getMenu($xml, $categories, $subcategories, $names, $images) { 
     $output = '<ul>'; 
      foreach(array_keys($images) as $n) {  
       $output .= '<li class="animals" data-tags="'.$names[$n].'">'; 
       $output .= '<img src="xml/'.$images[$n].'" width="75" height="75" alt="'.$names[$n].'" />'; 
       $output .= '</li>';  
      } 

     $output.= '</ul>'; 
     return array($output); 
    } 

    $result = getMenu($xml, $categories, $subcategories, $names, $images); 

    echo json_encode($result); 

    ?> 

Answer 1

從字面上有一千種方式你如何做到這一點。最直截了當的可能是xpath()。這是一種功能強大的XML查詢語言，值得學習。例如你$xml的SimpleXMLElement：

foreach ($xml->xpath('//category[not(. = following::category)]') as $category) { 
    echo "=== $category === \n"; 
    foreach ($xml->xpath("//animal[category = '$category']/subcategory[not(. = following::animal[category = '$category']/subcategory)]") as $subcategory) { 
     echo " = $subcategory =\n"; 
     foreach ($xml->xpath("//animal[category = '$category' and subcategory = '$subcategory']") as $animal) { 
      echo " * $animal->name ($animal->image)\n"; 
     } 
    } 
} 

輸出：

=== DOGS === 
    = small = 
    * Terrier (aaa.jpg) 
    * Havanese (bbb.jpg) 
    = large = 
    * Dalmatian (ccc.jpg) 

您進一步上可能要更換冗長的XPath字符串在那裏。隨着封閉的幫助和迭代器合計，它甚至有可能減少代碼很舒服：

foreach ($categories as $category) { 
    echo "=== $category === \n"; 
    foreach ($subcategories as $subcategory) { 
     echo " = $subcategory =\n"; 
     foreach ($animals as $animal) { 
      echo " * $animal->name ($animal->image)\n"; 
     } 
    } 
} 

這將允許稍後改變XML結構，並具有XPath的中央位置配置：

$categories = $vpath('//category[not(. = following::category)]'); 
$subcategories = $vpath('//animal[category = "%1$s"]/subcategory[not(. = following::animal[category = "%1$s"]/subcategory)]', [&$category]); 
$animals  = $vpath("//animal[category = '%s' and subcategory = '%s']", [&$category, &$subcategory]); 

我已經把這個例子在線作爲demo。

我的輸出就像帶縮進的文本一樣，但是要感謝foreach s，應該非常直接地將它轉換爲HTML。我把它作爲一個練習。