I’ve been playing with Fredrik Lundh’s ElementTree as an intuitive/pythonic way of processing XML. (While I like Aaron Swarz’s XML Tramp, it is presently unsupported; ElementTree is fast and has XPath support.)

ElementTree Conventions

• Parsing an XML document:

  from elementtree.ElementTree import parse

  tree = parse(filename)
doc = tree.getroot()

• Element type (name): print doc.tag

• Element text: print doc.text

• Elements have a list of children

  • iterate over children: for child in doc
  • get first and second (splice) child: doc[0:2]
  • get the child of element type book: doc.find(``'book')
  • append(), insert() and remove() are also supported
  • getiterator(tag) returns a list (or another iterable object) of all (descendent) subelements that has the given tag in document order

• Elements have a dict of attributes

  • get the attribute dictionary keys: book.keys()

  • get the attribute dictionary: book.items()

  • test for an attribute COLOR:

    if book.get('COLOR') is not None, or
    if 'COLOR' in book.attrib

  • get attribute COLOR value:

    book.attrib.get('COLOR'), or
    book.get('COLOR')

  • assign attribute value: book.set('COLOR', 'blue')

• No data structure is provided for accessing a parent node, however one can easily create a dictionary that yields the parent for any given node:

  • parent_map = dict([(c,p) for p in tree.getiterator() for c in p])

• XPath Support

  • Find all grandchildren of type ‘author’: doc.find('*/author')

• Namespaces (NS) uses James Clark notation:

  • NS qualified elment: doc = Element("{http://example.com}``doc")
  • NS qualified attribute: book.set('{http://example.com}COLOR', 'blue')

• To reserialize an object use print doc.write(outfile)

Ported/Archived Responses

Martin Thomas on 2007-04-25

Thanks for this useful pockert reference.
Just a quick note, “Find all grandchildren of type ‘author’: doc.find(’*/author’)” is incorrect..
the .find method only returns the first ofay items found.  The .findall method will do as described.

//m