php – simpleXML基于属性获取节点子节点

参见英文答案 > SimpleXML: Selecting Elements Which Have A Certain Attribute Value????????????????????????????????????2个
>???????????? Implementing condition in XPath ????????????????????????????????????2个
我试图通过其中一个属性解析我引用的节点的值.但我不确定语法

XML：

<data>

  <poster name="E-Verify" id="everify">

    <full_image url="e-verify-swa-poster.jpg"/>

    <full_other url=""/>

  </poster>


  <poster name="Minimum Wage" id="minwage">

    <full_image url="minwage.jpg"/>

    <full_other url="spa_minwage.jpg"/>

  </poster>
</data>

这里是我想要获取full_image的url值,其中poster id等于minwage：

$xml = simplexml_load_file('PosterData.xml');
$main_url = $xml->full_image[name] where poster[id] = "minwage";
//something like that.
echo $main_url;

Result: minwage.jpg

如果有人有任何资源涵盖这些东西请分享.

$xml = simplexml_load_file('PosterData.xml');

foreach ($xml->poster as $poster) {
    if ((string) $poster['id'] == 'minwage') {
        echo (string) $poster->full_image['url'];
    }
}