Simplest lxml parsing example

Below is an xml document that is about as simple as one can get.

<?xml version="1.0" encoding="UTF-8"?>
<cat>
  <name>Molly</name>
</cat>

Put that in a file called doc.xml.

Now how would you parse it with Python to get at the cat's name?

Use lxml, a Python xml parsing library.

The library is based on the API introduced by a prior library called ElementTree. It is now preferred over it, because lxml has extra features such as XPath queries.

import lxml.etree
tree = lxml.etree.parse('doc.xml')
cat_name = tree.xpath('/cat/name')[0].text
print cat_name # Molly

XPath is used above to define where the cat's name appears.

App Engine

To use lxml on Google App engine, put this in your app.yaml

libraries:
- name: lxml
  version: "latest"

Then you can just do "import lxml" in your code.

If in GoogleAppEngineLauncher (dev_appserver.py) you get "ImportError: No module named lxml", do remember to install locally too ("sudo pip install lxml").

More to read

Python XML processing with lxml

Bonus: origin of the lxml name

PS. I wanted to mention where the name "lxml" comes from here, but could not find the answer. If you know, let me know by email or @bemmu on Twitter.

Asking around on Twitter uncovered that the name "lxml" comes from it being based on libxml2, thanks codebyjeff and @faassen.