xml_namespace_example.py

"""An example of how to deal with XML namespaces using LXML.
"""

blob = b"""
<p:doc xmlns:p="http://my.de/fault/namespace">
  <p:title>The dog and the hog</p:title>
  <p:section>
    <p:title>The dog</p:title>
    <p:par>Once upon a time, ...</p:par>
    <p:par>And then ...</p:par>
  </p:section>
  <p:section>
    <p:title>The hog</p:title>
    <p:par>Sooner or later ...</p:par>
  </p:section>
</p:doc>
"""

from lxml import etree
from io import BytesIO

fake_file = BytesIO(blob)
doc = etree.parse(fake_file)
# or directly etree.fromstring(blob)
# but you're probably going to read this xml from a file

title1 = doc.xpath(
    "//p:title",
    namespaces={
        "p": "http://my.de/fault/namespace"
    }
)
assert len(title1) > 0

prefix = "p"
namespace = "http://my.de/fault/namespace"
title2 = doc.xpath(
    "//{}:title".format(prefix),
    namespaces={
        prefix: namespace
    }
)
assert title2 == title1

title3 = etree.ETXPath("//{http://my.de/fault/namespace}title")(doc)
assert title1 == title3