duanfan5012
2018-07-03 18:42
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PHP - 删除XML空节点

I found this code to remove empty nodes from and XML file but it isn't working correctly. It leaves an empty node that really needs to be removed. Yes, it is empty, just white space in it.

$domxml = new DOMDocument('1.0');
$domxml->preserveWhiteSpace = false;
$domxml->formatOutput = true;
$domxml->loadXML($this->response);
$this->response = $domxml->saveXML($domxml->documentElement);

Anyone know of a better way to do this?

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我发现此代码从XML文件中删除空节点但它无法正常工作。 它留下了一个真正需要删除的空节点。 是的,它是空的,只是空格。

  $ domxml = new DOMDocument('1.0'); 
 $ domxml-> preserveWhiteSpace = false; 
  $ domxml-> formatOutput = true; 
 $ domxml-> loadXML($ this-> response); 
 $ this-> response = $ domxml-> saveXML($ domxml-> documentElement);  
   
 
 

任何人都知道更好的方法吗?

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2条回答 默认 最新

  • dongzhenge2014 2018-07-04 08:13
    最佳回答

    In other words you would like to remove any element node that has no text content, no attribute, no children with text content or attributes and have a parent element node (are not the document element).

    Here is an Xpath function normalize-space() that converts any whitespace sequences to single spaces and strips them from the start/end. Any whitespace only content will result in an empty string.

    Xpath

    //* fetches any element node in the document in a list. You just need to add conditions.

    • Has no text content
      normalize-space(.) = ""
    • No attributes
      not(@*)
    • No descendant node with content (includes comments, ...)
      not(.//node()[normalize-space(.) != ""])
    • No descendant element nodes with attributes
      not(.//*[@*])
    • Has a parent element node
      parent::*

    Put together:

    $xml = <<<'XML'
    <foo>
      <bar></bar>
      <bar>123</bar>
      <bar foo="123"></bar>
      <bar><foo>   </foo></bar>
      <bar><!-- test --></bar>
    </foo>
    XML;
    
    $document = new DOMDocument();
    $document->preserveWhiteSpace = FALSE;
    $document->formatOutput = TRUE; 
    $document->loadXml($xml);
    $xpath = new DOMXpath($document);
    
    $expression = 
      '//*[
        normalize-space(.) = "" and 
        not(@*) and  
        not(.//node()[normalize-space(.) != ""]) and 
        not(.//*[@*]) and
        parent::*
      ]';
    
    $nodes = $xpath->evaluate($expression);
    for ($i = $nodes->length - 1; $i >= 0; $i--) {
      $nodes[$i]->parentNode->removeChild($nodes[$i]);
    }
    
    echo $document->saveXml();
    

    Output:

    <?xml version="1.0"?>
    <foo>
      <bar>123</bar>
      <bar foo="123"/>
      <bar>
        <!-- test -->
      </bar>
    </foo>
    
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