I'm trying to extract the HTML code of a table from a webpage using BeautifulSoup.
<table class="facts_label" id="facts_table">...</table>
I would like to know why the code bellow works with the "html.parser"
and prints back none
if I change "html.parser"
for "lxml"
.
#! /usr/bin/python
from bs4 import BeautifulSoup
from urllib import urlopen
webpage = urlopen('http://www.thewebpage.com')
soup=BeautifulSoup(webpage, "html.parser")
table = soup.find('table', {'class' : 'facts_label'})
print table
lxml is also a similar parser but driven by XML features than HTML. It has dependency on external C libraries. It is faster as compared to html5lib. Lets observe the difference in behavior of these two parsers by taking a sample tag example and see the output.
lxml is way faster than BeautifulSoup - this may not matter if all you're waiting for is the network. But if you're parsing something on disk, this may be significant.
lxml can make use of BeautifulSoup as a parser backend, just like BeautifulSoup can employ lxml as a parser. When using BeautifulSoup from lxml, however, the default is to use Python's integrated HTML parser in the html. parser module.
Speed. Scrapy is incredibly fast. Its ability to send asynchronous requests makes it hands-down faster than BeautifulSoup. This means that you'll be able to scrape and extract data from many pages at once.
There is a special paragraph in BeautifulSoup
documentation called Differences between parsers, it states that:
Beautiful Soup presents the same interface to a number of different parsers, but each parser is different. Different parsers will create different parse trees from the same document. The biggest differences are between the HTML parsers and the XML parsers.
The differences become clear on non well-formed HTML documents.
The moral is just that you should use the parser that works in your particular case.
Also note that you should always explicitly specify which parser are you using. This would help you to avoid surprises when running the code on different machines or virtual environments.
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