使用 xPath 访问 simpleXML 的值 [英] Using xPath to access values of simpleXML

问题描述

我的数据库中有一个包含设置的 XML 对象结果.

I have a XML object result from my database containing settings.

我正在尝试访问特定设置名称的值:

I am trying to access the values for a particular settingName:

    SimpleXMLElement Object
(
[settings] => Array
    (
        [0] => SimpleXMLElement Object
            (
                [settingName] => Test
                [settingDescription] => Testing
                [requireValue] => 1
                [localeID] => 14
                [status] => 1
                [value] => 66
                [settingID] => 5
            )

        [1] => SimpleXMLElement Object
            (
                [settingName] => Home Page Stats
                [settingDescription] => Show the Top 5 Teammate / Teamleader stats?
                [requireValue] => 0
                [localeID] => 14
                [status] => 0
                [value] => SimpleXMLElement Object
                    (
                    )

                [settingID] => 3
            )

    )

)

我尝试使用 xPath 并且到目前为止有这个:

I tried using xPath and have this so far:

$value = $fetchSettings->xpath("//settingName[text()='Test']/../value");

返回:

Array ( [0] => SimpleXMLElement Object ( [0] => 66 ) )

如何获取实际值而不仅仅是另一个数组/对象?

How can I get the actual value and not just another array/object?

对于上面的示例，最终结果将是 66.

The end result will just be 66 for the example above.

推荐答案

1. SimpleXMLElement::xpath() 返回搜索结果"的普通 PHP 数组；第一个结果将始终是索引 0 如果找到任何结果.
2. 每个搜索结果"都是一个 SimpleXMLElement 对象，它有一个神奇的 __toString() 获取节点直接文本内容的方法(包括 CDATA，但包括子节点内的文本等).调用它的最简单方法是使用 (string)$my_element;(int)$my_element 也会调用它，然后将结果转换为整数.

1. SimpleXMLElement::xpath() returns a plain PHP array of "search results"; the first result will always be index 0 if any results were found.
2. Each "search result" is a SimpleXMLElement object, which has a magic __toString() method for getting the direct text content of a node (including CDATA, but including text inside child nodes, etc). The simplest way to call it is with (string)$my_element; (int)$my_element will also invoke it, then convert the result to an integer.

所以:

 $xpath_results = $fetchSettings->xpath("//settingName[text()='Test']/../value");
 if ( count($xpath_results) > 0 ) {
      $value = (string)$xpath_results[0];
 }

<小时>

或者，DOMXPath 类可以返回元素和属性节点以外的结果，由于 DOM 更丰富的对象模型.例如，您可以使用一个以 //text() 结尾的 XPath 表达式来引用节点的文本内容，而不是节点本身(SimpleXML 将执行搜索，但会给您一个元素对象无论如何).

---

Alternatively, the DOMXPath class can return results other than element and attribute nodes, due to the DOM's richer object model. For instance, you can have an XPath expression ending //text() to refer to the text content of a node, rather than the node itself (SimpleXML will do the search, but give you an element object anyway).

缺点是使用起来比较冗长，但幸运的是您可以混合和匹配两组函数(使用 dom_import_simplexml() 及其对应物)，因为它们具有相同的底层表示:

The downside is it's rather more verbose to use, but luckily you can mix and match the two sets of functions (using dom_import_simplexml() and its counterpart) as they have the same underlying representation:

 // WARNING: Untested code. Please comment or edit if you find a bug!
 $fetchSettings_dom = dom_import_simplexml($fetchSettings);
 $xpath = new DOMXPath($fetchSettings_dom->ownerDocument);
 $value = $xpath->evaluate(
      "//settingName[text()='Test']/../value/text()",
      $fetchSettings_dom
 );

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