At 02:20 19.09.2005, James H. wrote: >Greetings! I'm new to Python and am struggling a little with "and" and >"or" logic in Python. Since Python always ends up returning a value >and this is a little different from C, the language I understand best >(i.e. C returns non-zero as true, and zero as false), is there anything >I should be aware of given Python's different approach? Namely any >pitfalls or neat tricks that make the Python approach cool or save my >butt.
to make sure that an operation yields a boolean value wrap a bool() around an expression. None, 0 and objects which's len is 0 yield False. so you can also do stuff like that: >>> a = [] >>> b = [1,2,3] >>> a or b [1, 2, 3] >>> class Foo: ... def __len__(self): return 0 ... >>> class Bar: ... def __len__(self): return 1 ... >>> foo = Foo() >>> bar = Bar() >>> foo or bar <__main__.Bar instance at 0x7D289940> sven. -- http://mail.python.org/mailman/listinfo/python-list
