Op 23-06-16 om 12:59 schreef Marko Rauhamaa: > Antoon Pardon <antoon.par...@rece.vub.ac.be>: > >> Op 23-06-16 om 11:53 schreef Marko Rauhamaa: >> Maybe something like this: >> >> def empty(sq): >> try: >> iter(sq).next() >> except StopIteration: >> return False >> except: >> raise TypeError >> else: >> return True > That may or may not be as effective as a boolean check. The point is, > Python has already declared that __bool__ is the canonical emptiness > checker. You could even say that it's the principal purpose of the > __bool__ method.
I think it is wrong to say __bool__ is the canonical emptiness checker. It can be used for anything where you somehow think it is reasonable to make a distinction between truthy and falsy. Even when talking about emptyness doesn't make sense. The function above at least raises an exception in a lot of cases where the class provides booly behaviour yet emptyness wouldn't make sense. Would it be worth while? That you have to decide for yourself. -- Antoon. -- https://mail.python.org/mailman/listinfo/python-list
