php根据其他节点值从xml获取节点值

Question

I have currently an xml file that is formatted as follows:

    <SKUQuestions>
       <SKUQuestion>
          <Tag>FrontCamaraWorks</Tag>
          <Question>Does the front Camera Work?</Question>
          <Answer>Yes</Answer>
       </SKUQuestion>
       <SKUQuestion>
          <Tag>BackCamaraWorks</Tag>
          <Question>Does the Rear Camera Work?</Question>
          <Answer>No</Answer>
       </SKUQuestion>
    </SKUQuestions>

I am currently getting the info from the "answer" nodes by calling where it occurs in the xml for example:

    $qFrontCameraWorks = $data['skuQuestions']->SKUQuestion[4];
    $data['frontCameraWorks'] = str_replace("'", "\'", $qFrontCameraWorks->Answer);

my problem is the xml files don't always come to me with the questions in the same order.

So, I was wanting to figure a way to query within a "SKUquestion" node if the "tag" is one thing then it would return the value of the "answer" node within that same SKUquestion node.

for example if the tag is "FrontCamaraWorks" then $data['frontCameraWorks'] is yes.

Answer 1

Simply run an XPath query expression. As information, XPath is a declarative language used to reference parts of XML documents. PHP's SimpleXMLElement class can run XPath queries returned in arrays:

$xmlstr = "<SKUQuestions>
                <SKUQuestion>
                   <Tag>FrontCamaraWorks</Tag>
                   <Question>Does the front Camera Work?</Question>
                   <Answer>Yes</Answer>
                </SKUQuestion>
                <SKUQuestion>
                   <Tag>BackCamaraWorks</Tag>
                   <Question>Does the Rear Camera Work?</Question>
                   <Answer>No</Answer>
                </SKUQuestion>
            </SKUQuestions>";

# LOAD STRING XML
$xml = new SimpleXMLElement($xmlstr);

# RUN XPATH QUERY
$queryResult = $xml->xpath('//SKUQuestion[Tag="FrontCamaraWorks"]/Answer');

# OUTPUT VALUE
echo $queryResult[0];
# Yes

Alternatively, you can use PHP's DOMXPath using its query() method which returns a DOMNodelist (not array):

# LOAD STRING XML
$xmldoc = new DOMDocument();
$xmldoc->loadXML($xmlstr);

# INITIALIZE AND RUN QUERY
$xpathvar = new DOMXPath($xmldoc);    
$queryResult = $xpathvar->query('//SKUQuestion[Tag="FrontCamaraWorks"]/Answer');

# ITERATE DOM NODE LIST
foreach($queryResult as $result){
    echo $result->nodeValue;
}
# Yes