緩衝或移動PHP數據以顯示在網頁的不同部分

Question

我正在使用XMLReader解析一個非常大的XML文件。

$reader = new XMLReader; 
$reader->open('products.xml'); 
$dom = new DOMDocument; 
$xpath = new DOMXpath($dom); 

while ($reader->read() && $reader->name !== 'product') { 
continue; 
} 

while循環用於顯示基於用戶輸入的相關數據以及使用XML值構建數組。

while ($reader->name === 'product') { 
$node = $dom->importNode($reader->expand(), TRUE); 

if ($xpath->evaluate('number(price)', $node) > $price_submitted) { 

$category = $xpath->evaluate('string(@category)', $node); 
$name = $xpath->evaluate('string(name)', $node); 
$price = $xpath->evaluate('number(price)', $node); 

// Relevant search results displayed here: 
echo "Category: " . $category . ". "; 
echo "Name: " . $name . ". "; 
echo "Price: " . $price . ". "; 


$nameArray[] = $name; 

} 
$reader->next('product'); 
} 

下面的foreach循環使用上面構建的while循環中的數組。我需要這些值（顯示在下面的foreach循環中）在while循環顯示相關搜索結果之前顯示。使用XMLReader，每次解析XML時只能執行一個while循環，而且由於內存和開銷問題，我不想再解析它兩次。做這個的最好方式是什麼？

foreach ($nameArray as $names) { 
echo $names . " "; 
} 

Answer 1

那麼......沒有太多的選擇。最有效實現了直接的方法是在存儲陣列類別/名稱/價格，而不是直接將它們輸出的：

<?php 
$data = array(); 
while ($reader->name === 'product') { 
    $node = $dom->importNode($reader->expand(), TRUE); 

    if ($xpath->evaluate('number(price)', $node) > $price_submitted) { 
     $category = $xpath->evaluate('string(@category)', $node); 
     $name = $xpath->evaluate('string(name)', $node); 
     $price = $xpath->evaluate('number(price)', $node); 

     $data[] = array($category, $name, $price); 
     $nameArray[] = $name; 
    } 

    $reader->next('product'); 
} 

foreach ($nameArray as $names) { 
    echo $names . " "; 
} 

foreach ($data as $datum) { 
    // Relevant search results displayed here: 
    echo "Category: " . $datum[0] . ". "; 
    echo "Name: " . $datum[1] . ". "; 
    echo "Price: " . $datum[2] . ". "; 
} 

萬一不行內存明智的（你提到XML文件是真正的大）您應該使用db或文件備份的臨時存儲