If you have an XML as shown below and you use XML parser in pyquery 1.1.1, then there is no quick way to select those with namespaces:

<?xml version="1.0" encoding="UTF-8" ?>
<foo xmlns:bar="http://example.com/bar" xmlns:bar2="http://example.com/bar2">

A simplest workaround is to load it with HTML parser, but you will get two indistinct elements of <blah/>. The more proper way is to build your own CSS selector:

from pyquery import PyQuery as pq
from lxml.cssselect import CSSSelector
d = pq(xml, parser='xml')
sel = CSSSelector('bar|blah', namespaces={'bar': 'http://example.com/bar'})
print sel(d[0])[0].text, pq(sel(d[0])).text()
sel = CSSSelector('bar2|blah', namespaces={'bar2': 'http://example.com/bar2'})
print sel(d[0])[0].text, pq(sel(d[0])).text()

A valid CSS selector for namespace in lxml is using | to separate namespace and tag names. With correct syntax, you also need to tell the namespaces by giving a dict as shown above. The results, list of elements, can be fed into pyquery, then you can use pyquery to carry out more selection.

I made a patch to pyquery, it will be easier if it gets pulled. The code would look like:

namespaces = {'bar': 'http://example.com/bar',
              'bar2': 'http://example.com/bar2'}
print pq('bar|blah', xml, parser='xml', namespaces=namespaces)
print d('bar2|blah', namespaces=namespaces).text()