PHP-从XML提要获取数据

我有以下代码：

<?php

  $url = 'http://www.floatrates.com/daily/gbp.xml';
  $xml = simplexml_load_file($url) or die("feed not loading");

  foreach ($xml as $val) {
    echo "<pre>" . print_r($val) . "</pre>";
  }

?>

我怎么才能只拿到美元？然后提取汇率

我试过了

if ($val->targetCurrency == "USD") {
  echo $val->exchangeRate;
}

---

但是现在还不行

多亏了Robbie的链接：

$url = 'http://www.floatrates.com/daily/gbp.xml';
$xml = simplexml_load_file($url) or die("feed not loading");

$results = $xml->xpath('/channel/item/targetCurrency[.="USD"]/following-sibling::exchangeRate');

$exchangeRate = (float)$results[0];

---

您也可以使用XPath来实现这一点

有关基本用法的示例

if ($val->targetCurrency == "USD") {
  echo $val->exchangeRate;
}

$url = 'http://www.floatrates.com/daily/gbp.xml';
$xml = simplexml_load_file($url) or die("feed not loading");

$results = $xml->xpath('/channel/item/targetCurrency[.="USD"]/following-sibling::exchangeRate');

$exchangeRate = (float)$results[0];