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html5libvscssselect

MIT License 83 14 1,092
18.9 million (month) Jul 30 2007 1.1(3 years ago)
281 8 21 BSD
1.2.0(1 year, 5 months ago) Apr 14 2012 8.3 million (month)

html5lib is a pure-python library for parsing HTML. It is designed to conform to the WHATWG HTML specification, as is implemented by all major web browsers.

As html5lib is implemented in pure-python it is significantly slower than alternatives powered by lxml (like parsel or beautifulsoup). However, html5lib implements a more true html5 parsing which can represent HTML tree more correctly than alternatives.

cssselect is a BSD-licensed Python library to parse CSS3 selectors and translate them to XPath 1.0 expressions.

XPath 1.0 expressions can be used in lxml or another XPath engine to find the matching elements in an XML or HTML document.

cssselect is used by other popular Python packages like parsel and scrapy but can also be used on it's own to generate valid XPath 1.0 expressions for parsing HTML and XML documents in other tools.

Note that because XPath selectors are more powerful than CSS selectors this translation is only possible one way. Converting XPath to CSS selectors is impractical and not supported by cssselect.

Example Use


import html5lib
from html5lib import parse

html_doc = "<html><head><title>My Title</title></head><body></body></html>"
parsed = parse(html_doc)
title = parsed.getElementsByTagName("title")[0]
print(title.childNodes[0].nodeValue)
from cssselect import GenericTranslator, SelectorError

translator = GenericTranslator()
try:
    expression = translator.css_to_xpath('div.content')
    print(expression)
    'descendant-or-self::div[@class and contains(concat(' ', normalize-space(@class), ' '), ' content ')]'
except SelectorError as e:
    print(f'Invalid selector {e}')

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