Just to clarify here, the only time code raising a StopIteration will cause a for-loop to exit silently is if the StopIteration is raised in an __iter__ method, e.g.:
That was a little imprecise. What I should have said is "the only time code raising a StopIteration will cause a for-loop to exit silently is if the StopIteration is raised in the code that is executed under the iteration protocol."
So, using the legacy iterator protocol:
>>> class C: ... def __getitem__(self, index): ... if index > 3: ... raise IndexError ... if index == 1: ... raise StopIteration ... return index ... >>> for i in C(): ... print i ... 0
Or using a separate iterator object:
>>> class C(object): ... def __iter__(self): ... return I() ... >>> class I(object): ... def __init__(self): ... self.count = -1 ... def next(self): ... self.count += 1 ... if self.count == 1: ... raise StopIteration ... return self.count ... >>> for i in C(): ... print i ... 0
Or using a generator to create the iterator object:
>>> class C(object): ... def __iter__(self): ... for i in range(3): ... if i == 1: ... raise StopIteration ... yield i ... >>> for i in C(): ... print i ... 0
Basically, each of these raises a StopIteration in the equivalent of the .next method. If a function that raises a StopIteration is put into any of the places where my code says 'raise StopIteration', then that StopIteration will silently terminate the loop.
I don't believe there should be any other places where raising a StopIteration would silently terminate a loop.
Steve -- http://mail.python.org/mailman/listinfo/python-list
