You can store pretty much anything as an attribute of an elementtree Element instance, not just strings.
A recent comment got me experimenting with this. Tom mentioned “Attributes can only be text”, which is abso-smurfly correct for XML. But remember: ElementTree is not XML. If you don’t need to serialize to XML, you can hang whatever you like on Elements.
Extending my power plant elementtree example a bit, I create a simple class to represent an employee, then hang instances of it on elements in a nested structure:
from elementtree.ElementTree import Element
from elementtree.ElementTree import SubElement
class Emp(object):
"""A simple Employee
"""
def __init__(self, name, title):
self.name = name
self.title = title
# make some employee instances
burns = Emp("Monty", "CEO")
smithers = Emp("Waylon", "Flunkie")
karl = Emp("Carl", "Engineer")
lenny = Emp("Lenny", "Engineer")
homer = Emp("Homer","Safety Inspector")
# hang them on a tree
ceo = Element('e', emp=burns)
smithers_elem = SubElement(ceo, 'e', emp=smithers)
SubElement(smithers_elem, 'e', emp=karl)
SubElement(smithers_elem, 'e', emp=lenny)
SubElement(smithers_elem, 'e', emp=homer)
It’s gross because I create element labels that will never be used (“e”), and I can’t ever serialize the structure to XML (bummer), but if you need nested data in a hurry, it’s hard to beat.
Plus, I’m pretty sure that someone smarter than I could make this scenario cleaner by doing things like extending tostring to correctly serialize the Emp instances.
