How to overload Python's __bool__ method in 2.x?


I thought this should print "False", why is it printing "True"?

>>> class Foo(object):
...   def __bool__(self):
...     return False
>>> f = Foo()
>>> if f:
...   print "True"
... else:
...   print "False"
Asked By: dividebyzero



You should define __nonzero__() in Python 2.x. It was only renamed to __bool__() in Python 3.x. (The name __nonzero__() actually predates the introduction of the bool type by many years.)

Answered By: Sven Marnach