在PHP中从字符串中提取DOM元素 [英] Extract DOM-elements from string, in PHP
问题描述
可能存在重复:
使用php爬取html页面
>解析HTML的最佳方法
我有一个字符串变量我的php脚本,包含html页面。我如何从这个字符串中提取DOM元素?例如,在这个字符串中'< div class =someclass> text< / div>'
>,我希望变量'文字'。我该如何做到这一点?
您需要使用 DOMDocument
类,更具体地说,它的 loadHTML
方法,将您的HTML字符串加载到DOM对象中。
例如:
$ string =<<< HTML< b $ b< p>测试< / p>
< div class =someclass>文字< / div>
< p>另一个< / p>
HTML;
$ dom = new DOMDocument();
$ dom-> loadHTML($ string);
例如,就你而言,你可以使用基于这部分代码的东西: 在这里,您可以得到以下输出:
之后,您将可以操作DOM,使用例如 DOMXPath
$ xpath = new DOMXpath($ dom);
$ result = $ xpath-> query('// div [@ class =someclass]');
if($ result-> length> 0){
var_dump($ result-> item(0) - > nodeValue);
}
string'text'(length = 4)
也可以使用 DOMDocument 。 php.net/simplexml_load_stringrel =noreferrer> simplexml_load_string
和 SimpleXMLElement :: xpath
- 但对于复杂的操作,我通常更喜欢使用 DOMDocument
。
Possible Duplicates:
crawling a html page using php?
Best methods to parse HTML
I have one string-variable in my php-script, that contains html-page. How i can extract DOM-elements from this string?
For example, in this string '<div class="someclass">text</div>'
, i wish get variable 'text'. How i can do this?
You need to use the DOMDocument
class, and, more specifically, its loadHTML
method, to load your HTML string to a DOM object.
For example :
$string = <<<HTML
<p>test</p>
<div class="someclass">text</div>
<p>another</p>
HTML;
$dom = new DOMDocument();
$dom->loadHTML($string);
After that, you'll be able to manipulate the DOM, using for instance the DOMXPath
class to do XPath queries on it.
For example, in your case, you could use something based on this portion of code :
$xpath = new DOMXpath($dom);
$result = $xpath->query('//div[@class="someclass"]');
if ($result->length > 0) {
var_dump($result->item(0)->nodeValue);
}
Which, here, would get you the following output :
string 'text' (length=4)
As an alternative, instead of DOMDocument
, you could also use simplexml_load_string
and SimpleXMLElement::xpath
-- but for complex manipulations, I generally prefer using DOMDocument
.
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