How can I access namespaced XML elements using BeautifulSoup?

BeautifulSoup isn't a DOM library per se (it doesn't implement the DOM APIs). To make matters more complicated, you're using namespaces in that xml fragment. To parse that specific piece of XML, you'd use BeautifulSoup as follows:

from BeautifulSoup import BeautifulSoup

xml = """<xml>
  <web:Web>
    <web:Total>4000</web:Total>
    <web:Offset>0</web:Offset>
  </web:Web>
</xml>"""

doc = BeautifulSoup( xml )
print doc.find( 'web:total' ).string
print doc.find( 'web:offset' ).string

If you weren't using namespaces, the code could look like this:

from BeautifulSoup import BeautifulSoup

xml = """<xml>
  <Web>
    <Total>4000</Total>
    <Offset>0</Offset>
  </Web>
</xml>"""

doc = BeautifulSoup( xml )
print doc.xml.web.total.string
print doc.xml.web.offset.string

The key here is that BeautifulSoup doesn't know (or care) anything about namespaces. Thus web:Web is treated like a web:web tag instead of as a Web tag belonging to th eweb namespace. While BeautifulSoup adds web:web to the xml element dictionary, python syntax doesn't recognize web:web as a single identifier.

You can learn more about it by reading the documentation.

This is an old question but somebody might not know that at least BeautifulSoup 4 does handle namespaces well if you pass 'xml' as second argument to the constructor:

soup = BeautifulSoup("""<xml>
<web:Web>
<web:Total>4000</web:Total>
<web:Offset>0</web:Offset>
</web:Web>
</xml>""", 'xml')

print soup.prettify()
<?xml version="1.0" encoding="utf-8"?>
<xml>
 <Web>
  <Total>
   4000
  </Total>
  <Offset>
   0
  </Offset>
 </Web>
</xml>