从XML内容中使用PHP获取元素

huangapple
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英文:

Get elements from a XML content by PHP

问题

我正在尝试从这个XML内容中获取元素，但返回为空：

  1. <results>
  2.   <error>
  3.     <string>i</string>
  4.     <description>Make I uppercase</description>
  5.     <precontext></precontext>
  6.     <suggestions>
  7.         <option>I</option>
  8.     </suggestions>
  9.     <type>grammar</type>    
  10.   </error>
  11. </results>

这是提取语法类型元素的代码：

  1. $dom = new DOMDocument();
  2. $dom->loadXml($output);
  3. $params = $dom->getElementsByTagName('error'); // 查找部分
  4. $k=0;
  5. foreach ($params as $param) // 逐个处理每个部分
  6. {
  7.     if($param->type == "grammar"){
  8.         echo $param->description;
  9.     }else{
  10.         echo "other type";
  11.     }
  12. }

问题是脚本返回为空。

英文:

I am trying to get elements from this XML content but returns empty:

  1. &lt;results&gt;
  2.   &lt;error&gt;
  3.     &lt;string&gt;i&lt;/string&gt;
  4.     &lt;description&gt;Make I uppercase&lt;/description&gt;
  5.     &lt;precontext&gt;&lt;/precontext&gt;
  6.     &lt;suggestions&gt;
  7.         &lt;option&gt;I&lt;/option&gt;
  8.     &lt;/suggestions&gt;
  9.     &lt;type&gt;grammar&lt;/type&gt;    
  10.   &lt;/error&gt;
  11. &lt;/results&gt;

And this is my code to extract element type of grammar :

  1. $dom = new DOMDocument();
  2. $dom-&gt;loadXml($output);
  3. $params = $dom-&gt;getElementsByTagName(&#39;error&#39;); // Find Sections
  4. $k=0;
  5. foreach ($params as $param) //go to each section 1 by 1
  6. {
  7.     if($param-&gt;type == &quot;grammar&quot;){
  8.         echo $param-&gt;description;
  9.     }else{
  10.         echo &quot;other type&quot;;
  11.     }

Problem is the script returns empty.

答案1

得分: 1

你可以使用 simplexml_load_string()

  1. $output = '<results>
  2.           <error>
  3.             <string>i</string>
  4.             <description>将I大写</description>
  5.             <precontext></precontext>
  6.             <suggestions>
  7.                 <option>I</option>
  8.             </suggestions>
  9.             <type>语法</type>    
  10.           </error>
  11.         </results>';
  13. $xml = simplexml_load_string($output);
  15. foreach($xml->error as $item)
  16. {
  17.     //echo (string)$item->type;
  18.     
  19.     if($item->type == "语法"){
  21.     echo $item->description;
  23.     }else{
  24.      echo "其他类型";
  26.     }
  27. }
英文:

you can use simplexml_load_string()

  1.  $output = &#39;&lt;results&gt;
  2.       &lt;error&gt;
  3.         &lt;string&gt;i&lt;/string&gt;
  4.         &lt;description&gt;Make I uppercase&lt;/description&gt;
  5.         &lt;precontext&gt;&lt;/precontext&gt;
  6.         &lt;suggestions&gt;
  7.             &lt;option&gt;I&lt;/option&gt;
  8.         &lt;/suggestions&gt;
  9.         &lt;type&gt;grammar&lt;/type&gt;    
  10.       &lt;/error&gt;
  11.     &lt;/results&gt;&#39;;
  12.     
  13.     
  14.     $xml = simplexml_load_string($output);
  15.     
  16.     foreach($xml-&gt;error as $item)
  17.     {
  18.         //echo (string)$item-&gt;type;
  19.         
  20.         if($item-&gt;type == &quot;grammar&quot;){
  21.     
  22.         echo $item-&gt;description;
  23.     
  24.         }else{
  25.          echo &quot;other type&quot;;
  26.     
  27.         }
  28.     }

答案2

得分: 1

你显然没有配置PHP来报告错误，因为你的代码触发了以下错误：

注意：未定义属性：DOMElement::$type

你需要以与获取<error>相同的方式获取<type>，使用DOM方法，例如getElementsByTagName()。对于节点的值也是一样的：

  1. if ($param->getElementsByTagName('type')->length && $param->getElementsByTagName('type')[0]->nodeValue === 'grammar') {
  2.     // 随时可以添加其他检查：
  3.     echo $param->getElementsByTagName('description')[0]->nodeValue;
  4. } else {
  5.     echo "其他类型";
  6. }

演示

英文:

You apparently haven't configured PHP to report errors because your code triggers:

> Notice: Undefined property: DOMElement::$type

You need to grab &lt;type&gt; the same way you grab &lt;error&gt;, using DOM methods like e.g. getElementsByTagName(). Same for node value:

  1. if ($param-&gt;getElementsByTagName(&#39;type&#39;)-&gt;length &amp;&amp; $param-&gt;getElementsByTagName(&#39;type&#39;)[0]-&gt;nodeValue === &#39;grammar&#39;) {
  2.     // Feel free to add additional checks here:
  3.     echo $param-&gt;getElementsByTagName(&#39;description&#39;)[0]-&gt;nodeValue;
  4. }else{
  5.     echo &quot;other type&quot;;
  6. }

Demo

答案3

得分: 1

I think is this what you want.

  1. <?php
  3. $output = '<results>
  4.   <error>
  5.     <string>i</string>
  6.     <description>Make I uppercase</description>
  7.     <precontext></precontext>
  8.     <suggestions>
  9.         <option>I</option>
  10.     </suggestions>
  11.     <type>grammar</type>
  12.   </error>
  13. </results>';
  15. $dom = new DOMDocument();
  16. $dom->loadXml($output);
  17. $params = $dom->getElementsByTagName('error'); // Find Sections
  18. $k = 0;
  20. foreach ($params as $param) //go to each section 1 by 1
  21. {
  22.     $string = $param->getElementsByTagName("string")->item(0)->nodeValue;
  23.     $description = $param->getElementsByTagName("description")->item(0)->nodeValue;
  24.     $option = $param->getElementsByTagName("option")->item(0)->nodeValue;
  25.     $type = $param->getElementsByTagName("type")->item(0)->nodeValue;
  26.     echo $type;
  27.     if ($type == "grammar") {
  28.         echo $description;
  29.     } else {
  30.         echo "other type";
  31.     }
  32. }
  33. ?>
英文:

I think is this what you want.

  1.        &lt;?php
  2.     
  3.     $output  = &#39;&lt;results&gt;
  4.       &lt;error&gt;
  5.         &lt;string&gt;i&lt;/string&gt;
  6.         &lt;description&gt;Make I uppercase&lt;/description&gt;
  7.         &lt;precontext&gt;&lt;/precontext&gt;
  8.         &lt;suggestions&gt;
  9.             &lt;option&gt;I&lt;/option&gt;
  10.         &lt;/suggestions&gt;
  11.         &lt;type&gt;grammar&lt;/type&gt;    
  12.       &lt;/error&gt;
  13.     &lt;/results&gt;&#39;;
  14.     
  15.     $dom = new DOMDocument();
  16.     $dom-&gt;loadXml($output);
  17.     $params = $dom-&gt;getElementsByTagName(&#39;error&#39;); // Find Sections
  18.     $k=0;
  19.     
  20.     
  21.     foreach ($params as $param) //go to each section 1 by 1
  22.     {
  23.         $string = $param-&gt;getElementsByTagName( &quot;string&quot; )-&gt;item(0)-&gt;nodeValue;
  24.         $description = $param-&gt;getElementsByTagName( &quot;description&quot; )-&gt;item(0)-&gt;nodeValue;
  25.         $option = $param-&gt;getElementsByTagName( &quot;option&quot; )-&gt;item(0)-&gt;nodeValue;
  26.         $type = $param-&gt;getElementsByTagName( &quot;type&quot; )-&gt;item(0)-&gt;nodeValue;
  27.         echo $type;
  28.         if($type == &quot;grammar&quot;){
  29.             echo $description ;
  30.         }else{
  31.             echo &quot;other type&quot;;
  32.         }
  33.     }
  34. ?&gt;

答案4

得分: 1

你正在混合使用DOM和SimpleXML。这是可能的，但你需要使用simplexml_import_dom()将DOM元素节点转换为SimpleXML实例。

或者你可以使用XPath。getElementsByTagName()是一种低级DOM方法。使用XPath表达式可以更具体地访问，而且需要更少的代码。

  1. $document = new DOMDocument();
  2. $document->loadXML($xml);
  3. $xpath = new DOMXpath($document);
  5. foreach ($xpath->evaluate('//error') as $error) {
  6.     var_dump(
  7.         [
  8.             'type' => $xpath->evaluate('string(type)', $error),
  9.             'description' => $xpath->evaluate('string(description)', $error)
  10.         ]
  11.     );
  12. }

输出：

  1. array(2) {
  2.   ["type"]=>
  3.   string(7) "grammar"
  4.   ["description"]=>
  5.   string(16) "Make I uppercase"
  6. }

XPath表达式还允许使用条件，例如你可以使用//error[@type = "grammar"]来获取所有语法错误。

英文:

You're mixing DOM with SimpleXML. This is possible, but you would need to convert the DOM element node into a SimpleXML instance with simplexml_import_dom().

Or you use Xpath. getElementsByTagName() is a low level DOM method. Using Xpath expressions allows for more specific access with a lot less code.

  1. $document = new DOMDocument();
  2. $document-&gt;loadXML($xml);
  3. $xpath = new DOMXpath($document);
  5. foreach ($xpath-&gt;evaluate(&#39;//error&#39;) as $error) {
  6.     var_dump(
  7.         [
  8.             &#39;type&#39; =&gt; $xpath-&gt;evaluate(&#39;string(type)&#39;, $error),
  9.             &#39;description&#39; =&gt; $xpath-&gt;evaluate(&#39;string(description)&#39;, $error)
  10.         ]
  11.     );
  12. }

Output:

  1. array(2) {
  2.   [&quot;type&quot;]=&gt;
  3.   string(7) &quot;grammar&quot;
  4.   [&quot;description&quot;]=&gt;
  5.   string(16) &quot;Make I uppercase&quot;
  6. }

Xpath expressions allow for conditions as well, for example you could fetch all grammar errors using //error[@type = &quot;grammar&quot;].

huangapple
  • 本文由 发表于 2020年1月3日 15:16:50
  • 转载请务必保留本文链接：https://go.coder-hub.com/59574595.html
  • php
  • xml
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