XML handling in Python - a new teaching example using etree

Archive - Originally posted on "The Horse's Mouth" - 2015-12-09 09:21:06 - Graham Ellis
From the Python course just completed - a new example of XML handling, through the xml.etree.ElementTree module which was first available in Python 2.5.

  import xml.etree.ElementTree as etree

  try:

    tree = etree.parse(args.sourcefile[0])

  except Exception as e:

    print('FAILED to parse - reason %s' % e)

    exit(2)

An exception is thrown if the file cannot be opened, or if it can but contains badly formed XML, for example:

  munchkin:cambx grahamellis$ ./xmlparserdemo 6_context.xml 

  FAILED to parse - reason not well-formed (invalid token): line 3, column 1

Run with a properly formed and readable XML file, you can then iterate through the tree, and indeed do so recuresively if you wish:

  root = tree.getroot()

  for thing in root:

    print(thing)

    print(thing.attrib)

    print(thing.tag)

    print(thing.text)

    kids = thing.getchildren()

    print(kids)

    print("------------------")

Here's a sample of the results you may get (from a very short piece of XML in this case!)

  munchkin:cambx grahamellis$ ./xmlparserdemo -r 6_context.xml 

  <Element 'WatchedResource' at 0x10a037e10>

  {}

  WatchedResource

  WEB-INF/web.xml

  []

  ------------------

That's a single tag within the root, with no attributes (hence the empty dict) and no children (hence the empty list).

Complete program using this code [here] ... the program starts with an example of command line handling - the sample XML file I used is [here]. It also includes code to explore all elements of the tree ... Finally, the xml.etree.ElementTree module also includes tree searchimg and amendment methods.

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XML handling in Python - a new teaching example using etree