我正在用XMLReader解析一个非常大的XML文件。
$reader = new XMLReader;
$reader->open('products.xml');
$dom = new DOMDocument;
$xpath = new DOMXpath($dom);
while ($reader->read() && $reader->name !== 'product') {
continue;
}
while循环用于根据用户输入显示相关数据，并使用XML值构建数组。
while ($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;
}
$reader->next('product');
}
下面的foreach循环使用上面while循环中构建的数组。我需要这些值（显示在下面的foreach循环中）出现在上面的while循环显示相关搜索结果之前。使用XMLReader，每次解析XML时只能执行一个while循环，由于内存和开销问题，我不想解析两次。最好的方法是什么？
foreach ($nameArray as $names) {
echo $names . " ";
}
好吧…没有太多选择。最有效的直接方法是将类别/名称/价格存储在数组中，而不是直接输出：
<?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] . ". ";
}
在内存方面不起作用的情况下（您提到XML文件非常大），您应该使用数据库或文件支持的临时存储