解析h1，h2和h3标题标签内关键字外观的内容

问题描述：

Given a block of content, I'm looking to create a function in PHP to check for the existence of a keyword or keyword phrase inside an h1-h3 header tags...

For example, if the keyword was "Blue Violin" and the block of text was...

You don't see many blue violins. Most violins have a natural finish. <h1>If you see a blue violin, its really a rarity</h1>

I'd like my function to return:

The keyword phrase does appear in an h1 tag
The keyword phrase does not appear in an h2 tag
The keyword phrase does not appear in an h2 tag

给定一个内容块，我想在PHP中创建一个函数来检查关键字是否存在或h1-h3标题内的关键字短语...... p>

例如，如果关键字为“ Blue Violin strong>”，则文本块为.. 。 p>

你没有看到很多蓝色小提琴。大多数小提琴都有自然的光洁度。＆lt; h1＆gt;如果你看到一把蓝色的小提琴，它真的很罕见＆lt; / h1＆gt; em> p>

我希望我的功能能够回归： p>

关键字词组 strong>出现在h1标记中 li>
关键字词组不会 strong>出现在h2标记中 li>
关键字词组不 strong>出现在h2标记中 li> ul> div >

答

You can use DOM and the following XPath for this:

/html/body//h1[contains(.,'Blue Violin')]

This would match all h1 element inside the body element containing the phrase "Blue Violin" either directly or in a subnode. If it should only occur in the direct TextNode, change the . to text(). The results are returned in a DOMNodeList.

Since you only want to know if the phrase appears, you can use the following code:

$dom = new DOMDocument;
$dom->load('NewFile.xml');
$xPath = new DOMXPath($dom);
echo $xPath->evaluate('count(/html/body//h1[contains(.,"Blue Violin")])');

which will return the number of nodes matching this XPath. If your markup is not valid XHTML, you will not be able to use loadXML. Use loadHTML or loadHTMLFile instead. In addition, the XPath will execute faster if you give it a direct path to the nodes. If you only have one h1, h2 and h3 anyway, substitute the //h1 with a direct path.

Note that contains is case-sensitive, so the above will not match anything due to the Mixed Case used in the search phrase. Unfortunately, DOM (or better the underlying libxml) does only support XPath 1.0. I am not sure if there is an XPath function to do a case-insensitive search, but as of PHP 5.3, you can also use PHP inside an XPath, e.g.

$dom = new DOMDocument;
$dom->load('NewFile.xml');
$xpath = new DOMXPath($dom);
$xpath->registerNamespace("php", "http://php.net/xpath");
$xpath->registerPHPFunctions();
echo $xpath->evaluate('count(/html/body//h1[contains(php:functionString("strtolower", .),"blue violin")])');

so in case you need to match Mixed Case phrases or words, you can lowercase all text in the searched nodes before checking it with contains or use any other PHP function you may find useful here.

答

Instead of including PHP functions into the class, you can, as well, simply convert the Xpath PHP object into a regular PHP array and then search directly using regular string searching functions from PHP: http://fsockopen.com/php-programming/your-final-stop-for-php-xpath-case-insensitive

解析h1，h2和h3标题标签内关键字外观的内容

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