Adding attributes to existing elements, removing elements, etc with lxml

Question

I parse in the XML using

from lxml import etree

tree = etree.parse('test.xml', etree.XMLParser())

Now I want to work on the parsed XML. I'm having trouble removing elements with namespaces or just elements in general such as

<rdf:description><dc:title>Example</dc:title></rdf:description>

and I want to remove that entire element as well as everything within the tags. I also want to add attributes to existing elements as well. The methods I need are in the Element class but I have no idea how to use that with the ElementTree object here. Any pointers would definitely be appreciated, thanks

Answer 1

You can get to the root element via this call: root=tree.getroot()

Using that root element, you can use findall() and remove elements that match your criteria:

deleteThese = root.findall("title")
for element in deleteThese: root.remove(element)

Finally, you can see what your new tree looks like with this: etree.tostring(root, pretty_print=True)

Here is some info about how find/findall work: http://infohost.nmt.edu/tcc/help/pubs/pylxml/class-ElementTree.html#ElementTree-find

To add an attribute to an element, try something like this:

root.attrib['myNewAttribute']='hello world'

Answer 2

The remove method should do what you want:

>>> from lxml import etree
>>> from StringIO import StringIO

>>> s = '<Root><Description><Title>foo</Title></Description></Root>'
>>> tree = etree.parse(StringIO(s))

>>> print(etree.tostring(tree.getroot()))
<Root><Description><Title>foo</Title></Description></Root>

>>> title = tree.find('//Title')
>>> title.getparent().remove(title)
>>> etree.tostring(tree.getroot())
'<Root><Description/></Root>'

>>> print(etree.tostring(tree.getroot()))
<Root><Description/></Root>