New submission from Steven D'Aprano <st...@pearwood.info>: I'm not sure if this is a documentation bug or a behaviour bug, or possibly both.
The documentation warns about adding or deleting items from a dict while iterating over it: "Using iteritems() while adding or deleting entries in the dictionary will raise a RuntimeError." http://docs.python.org/library/stdtypes.html#dict.iteritems Same for other dict iterators. However, you can add and delete items, so long as the overall size of the dict doesn't change. Consequently, some modifications to the dict aren't caught, leading to various misbehaviour in (at least) Python 2.5 and 2.6. Some dicts appear to "run too long": >>> d = dict(x=3, y=4) # Two items >>> it = d.iteritems() >>> it.next() # One ('y', 4) >>> del d['y'] >>> d['z'] = 5 >>> it.next() # Two ('x', 3) >>> it.next() # Three ('z', 5) While others run too short: >>> d = {-1: 'aa', -2: 'bb'} # Two items >>> it = d.iteritems() >>> it.next() # One (-2, 'bb') >>> del d[-1] >>> d[0] = 'cc' >>> it.next() Traceback (most recent call last): File "<stdin>", line 1, in <module> StopIteration ---------- assignee: georg.brandl components: Documentation, Interpreter Core messages: 87729 nosy: georg.brandl, stevenjd severity: normal status: open title: Dict fails to notice addition and deletion of keys during iteration type: behavior versions: Python 2.5, Python 2.6 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue6017> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
