PHP Xpath为属性名称为"author"的节点提取值. [英] PHP Xpath extracting a value for a node with attribute name="author"

问题描述

我正在尝试解析一些XML数据以获得某个属性的值-具体来说，我想找到作者.以下是一个非常简短但有效的示例. R节点重复多次.

I'm trying to parse some XML data to get the value of a certain attribute - Specifically, I want to find the author. Below is a very cut-down but valid example. The R node is repeated multiple times.

<GSP VER="3.2">
    <RES SN="1" EN="10">
        <R N="4" MIME="application/pdf">
            <Label>_cse_rvfaxixpaw0</Label>
            <PageMap>
                <DataObject type="metatags">
                    <Attribute name="creationdate" value="D:20021024104222Z"/>
                    <Attribute name="author" value="Diana Van Winkle"/>
                </DataObject>
            </PageMap>
        </R>
    </RES>
</GSP>

我目前正在这样做:

$XML = simplexml_load_string($XMLResult);
$XMLResults = $XML->xpath('/GSP/RES/R');
foreach($XMLResults as $Result) {
    $Label = $Result->Label;
    $Author = ""; // <-- How do I get this?
}

有人可以向我解释如何提取作者"属性吗? author属性最多可以出现1次，但可能根本不存在(我自己可以解决)

Can someone please explain to me how I can pull out the "author" attribute? The author attribute will be present a maximum of 1 times but may not be present at all (I can handle that myself)

推荐答案

以下是解决方案.基本上，您可以使XPath退出结果节点，以获取名称属性等于author的所有属性元素.

Here is the solution. Basically you can make an XPath call off the result node to get all attribute elements with the name attribute equal to author.

然后您检查并确保结果返回，如果返回，则它将为index [0]，因为XPath调用返回结果数组.然后，使用attributes()函数获取属性的关联数组，最后获取所需的值.

Then you check and make sure a result came back, and if it did, it will be index[0] since XPath calls return an array of results. Then you use the attributes() function to get an associate array of the attribute, finally getting the value you want.

$XML = simplexml_load_string($xml_string);
$XMLResults = $XML->xpath('/GSP/RES/R');
foreach($XMLResults as $Result) {
    $Label = $Result->Label;
    $AuthorAttribute = $Result->xpath('//Attribute[@name="author"]');
    // Make sure there's an author attribute
    if($AuthorAttribute) {
      // because we have a list of elements even if there's one result
      $attributes = $AuthorAttribute[0]->attributes();
      $Author = $attributes['value'];
    }
    else {
      // No Author
    }
}

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