domcrawlervslxml
DOMCrawler library is part of the Symfony Components project and provides an easy way to traverse and manipulate HTML and XML documents using the Document Object Model (DOM) in PHP.
DOMcrawler supports both CSS selectors and XPath for HTML document parsing and is one the most popular HTML parsing tools used in web scraping with PHP.
lxml is a low-level XML and HTML tree processor. It's used by many other libraries such as parsel or beautifulsoup for higher level HTML parsing.
One of the main features of lxml is its speed and efficiency.
It is built on top of the libxml2 and libxslt C libraries, which are known for their high performance and low memory footprint.
This makes lxml well-suited for processing large and complex XML and HTML documents.
One of the key components of lxml is the ElementTree API, which is modeled after the ElementTree API from the Python standard library's xml module. This API provides a simple and intuitive way to access and manipulate the elements and attributes of an XML or HTML document. It also provides a powerful and flexible Xpath engine that allows you to select elements based on their names, attributes, and contents.
Another feature of lxml is its support for parsing and creating XML documents using the XSLT standard. The lxml library provides a powerful and easy-to-use interface for applying XSLT stylesheets to XML documents, which can be used to transform and convert XML documents into other formats, such as HTML, PDF, or even other XML formats.
For web scraping it's best to use other higher level libraries that use lxml like parsel or beautifulsoup
Highlights
Example Use
use Symfony\Component\DomCrawler\Crawler;
$html = '<html><body><h1 class="title">Hello World</h1></body></html>';
$crawler = new Crawler($html);
// Find all elements using CSS selectors
$elements = $crawler->filter('.title')i;
// or XPath
$elements = $crawler->filterXPath('//h1');
// Print the text content of the elements
foreach ($elements as $element) {
echo $element->textContent;
}
from lxml import etree
# this is our HTML page:
html = """
<head>
<title>Hello World!</title>
</head>
<body>
<div id="product">
<h1>Product Title</h1>
<p>paragraph 1</p>
<p>paragraph2</p>
<span class="price">$10</span>
</div>
</body>
"""
tree = tree.fromstring(html)
# for parsing, LXML only supports XPath selectors:
tree.xpath('//span[@class="price"]')[0].text
"$10"