On 28/09/2005, at 11:05 PM, Simon Brunning wrote: > On 9/28/05, could ildg <[EMAIL PROTECTED]> wrote: > >> Python is wonderful except that it has no real private and protected >> properties and methods. >> Every py object has dict so that you can easily find what fields >> and methods >> an obj has, this is very convenient, but because of this, py is >> very hard >> to support real private and protected? > > My convention, attributes with names prefixed with a single underscore > are private. There's nothing to stop anyone using these, but, well, if > you take the back off the radio, the warranty is void.
I'm not sure why I haven't seen this mentioned yet, but a leading double-underscore does really make a member private: >>> class f(object): ... def __init__(self): ... self.__f = 1 ... >>> a = f() >>> a.__f Traceback (most recent call last): File "<stdin>", line 1, in ? AttributeError: 'f' object has no attribute '__f' >>> dir(a) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__', '_f__f'] As you see, it's there in the dict, but it's obfuscated - but that's all that other languages do anyway. Anyone that takes advantage of that to get hold of members like this should have a very good reason for doing so. Just think of a single leading underscore as protected, and double leading underscores as private, and you'll be fine. As Simon said, people can still access these, but the consenting adults rule applies. =Tony.Meyer -- http://mail.python.org/mailman/listinfo/python-list
