Why does bool(xml.etree.ElementTree.Element) evaluate to False?
As it turns out, Element
objects are considered a False
value if they have no children.
I found this in the source:
def __nonzero__(self):
warnings.warn(
"The behavior of this method will change in future versions. "
"Use specific 'len(elem)' or 'elem is not None' test instead.",
FutureWarning, stacklevel=2
)
return len(self._children) != 0 # emulate old behaviour, for now
Even the inline comment agrees with you -- this behavior is iffy ;)
From the docs:
http://docs.python.org/library/xml.etree.elementtree.html#element-objects
Caution: Elements with no subelements will test as False. This behavior will change in future versions. Use specific len(elem) or elem is None test instead.