selectolax

A fast HTML5 parser with CSS selectors, written in Cython, using Modest and Lexbor engines.

Installation

From PyPI using pip:

pip install selectolax

If installation fails due to compilation errors, you may need to install Cython:

pip install selectolax[cython]

This usually happens when you try to install an outdated version of selectolax on a newer version of Python.

Development version from GitHub:

git clone --recursive  https://github.com/rushter/selectolax
cd selectolax
pip install -r requirements_dev.txt
python setup.py install

How to compile selectolax while developing:

make clean
make dev

Basic examples

Here are some basic examples to get you started with selectolax:

Parsing HTML and extracting text:

In [1]: from selectolax.lexbor import LexborHTMLParser
   ...:
   ...: html = """
   ...: <h1 id="title" data-updated="20201101">Hi there</h1>
   ...: <div class="post">Lorem Ipsum is simply dummy text of the printing and typesetting industry. </div>
   ...: <div class="post">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</div>
   ...: """
   ...: tree = LexborHTMLParser(html)

In [2]: tree.css_first('h1#title').text()
Out[2]: 'Hi there'

In [3]: tree.css_first('h1#title').attributes
Out[3]: {'id': 'title', 'data-updated': '20201101'}

In [4]: [node.text() for node in tree.css('.post')]
Out[4]:
['Lorem Ipsum is simply dummy text of the printing and typesetting industry. ',
 'Lorem ipsum dolor sit amet, consectetur adipiscing elit.']

Using advanced CSS selectors

In [1]: html = "<div><p id=p1><p id=p2><p id=p3><a>link</a><p id=p4><p id=p5>text<p id=p6></div>"
   ...: selector = "div > :nth-child(2n+1):not(:has(a))"

In [2]: for node in LexborHTMLParser(html).css(selector):
   ...:     print(node.attributes, node.text(), node.tag)
   ...:     print(node.parent.tag)
   ...:     print(node.html)
   ...:
{'id': 'p1'}  p
div
<p id="p1"></p>
{'id': 'p5'} text p
div
<p id="p5">text</p>

Using lexbor-contains CSS pseudo-class to match text

from selectolax.lexbor import LexborHTMLParser
html = "<div><p>hello </p><p id='main'>lexbor is AwesOme</p></div>"
parser = LexborHTMLParser(html)
# Case-insensitive search
results = parser.css('p:lexbor-contains("awesome" i)')
# Case-sensitive search
results = parser.css('p:lexbor-contains("AwesOme")')
assert len(results) == 1
assert results[0].text() == "lexbor is AwesOme"

• More examples

Available backends

Selectolax supports two backends: Modest and Lexbor. By default, all examples use the Lexbor backend. Most of the features between backends are almost identical, but there are some differences.

As of 2024, the preferred backend is Lexbor. The Modest backend is still available for compatibility reasons and the underlying C library that selectolax uses is not maintained anymore.

To use lexbor, just import the parser and use it in the similar way to the HTMLParser.

In [1]: from selectolax.lexbor import LexborHTMLParser

In [2]: html = """
   ...: <title>Hi there</title>
   ...: <div id="updated">2021-08-15</div>
   ...: """

In [3]: parser = LexborHTMLParser(html)
In [4]: parser.root.css_first("#updated").text()
Out[4]: '2021-08-15'

Simple Benchmark

• Extract title, links, scripts and a meta tag from main pages of top 754 domains. See examples/benchmark.py for more information.

Package	Time
Beautiful Soup (html.parser)	61.02 sec.
lxml / Beautiful Soup (lxml)	9.09 sec.
html5_parser	16.10 sec.
selectolax (Modest)	2.94 sec.
selectolax (Lexbor)	2.39 sec.

Links

• selectolax API reference and examples
• Video introduction to web scraping using selectolax
• How to Scrape 7k Products with Python using selectolax and httpx
• Modest introduction
• Modest benchmark
• Python benchmark
• Another Python benchmark
• Universal interface to lxml and selectolax

License

• Modest engine — LGPL2.1
• lexbor engine — Apache-2.0 license
• selectolax - MIT

Contributors

Thanks to all the contributors of selectolax!