基于属性打印 XML 文档的一部分？

Question

可能的重复：
SimpleXML根据属性值获取元素内容

我看过通过几个相关主题但找不到答案。

我如何打印，例如美元货币的 curr 值？

            <?xml version="1.0"?>
            <currencies>
                <currency id="AUD">
                        <curr>Australian dollar</curr>
                        <loc>Australia, Australian Antarctic Territory, Christmas Island, Cocos (Keeling) Islands, Heard and McDonald Islands, Kiribati, Nauru, Norfolk Island, Tuvalu</loc>
                </currency>
                <currency id="USD">
                        <curr>United States Dollar</curr>
                        <loc>American Samoa, British Indian Ocean Territory, Caribbean Netherlands, Ecuador, El Salvador, Guam, Haiti, Marshall Islands, Micronesia, Northern Mariana Islands, Palau, Panama, Puerto Rico, Timor-Leste, Turks and Caicos Islands, United States, U.S. Virgin Islands, Barbados (as well as Barbados Dollar), Bermuda (as well as Bermudian Dollar), Zimbabwe</loc>
                </currency>
            </currencies>

我可以通过这样做来打印我想要的内容：

    foreach($xml as $currency) {
        echo $currency[0]->curr;
    }   

但这并不完全是我想要的。另外，我的 XML 标记是否适合我想要实现的目标，或者是否可以通过更简单的方法来实现？

Answer 1

使用 XPath 语法：http://php.net/manual/simplexmlelement.xpath.php

$string = '<?xml version="1.0"?>
            <currencies>
                <currency id="AUD">
                        <curr>Australian dollar</curr>
                        <loc>Australia, Australian Antarctic Territory, Christmas Island, Cocos (Keeling) Islands, Heard and McDonald Islands, Kiribati, Nauru, Norfolk Island, Tuvalu</loc>
                </currency>
                <currency id="USD">
                        <curr>United States Dollar</curr>
                        <loc>American Samoa, British Indian Ocean Territory, Caribbean Netherlands, Ecuador, El Salvador, Guam, Haiti, Marshall Islands, Micronesia, Northern Mariana Islands, Palau, Panama, Puerto Rico, Timor-Leste, Turks and Caicos Islands, United States, U.S. Virgin Islands, Barbados (as well as Barbados Dollar), Bermuda (as well as Bermudian Dollar), Zimbabwe</loc>
                </currency>
            </currencies>';

$xml = new SimpleXMLElement($string);
var_dump($xml->xpath('//currency[@id="USD"]');

Answer 2

尝试

$data = simplexml_load_string($xml);
foreach($data->currencies as $currency) {
    // $currency->curr.. etc
]