class baseClass(object): __Something = "Dumb!"
def getSomething( self ): return self.__Something
class subClass(baseClass): def setSomething( self , aSomething ): self.__Something = aSomething
anObject = subClass() anObject.setSomething("Cool!") print anObject.getSomething()
Your mistake is using '__' names when they aren't necessary. '__' names are mangled with the class name:
py> class B(object):
... __x = False
... def __init__(self):
... self.__x = 1
... def getx(self):
... return self.__x
...
py> class C(object):
... def setx(self, x):
... self.__x = x
...
py> vars(B())
{'_B__x': 1}
py> vars(C())
{}Note that C instances don't get __x variables because of the mangling.
Someone please show me the pythonish way to do this!
A number of suggestions:
(1) Generally, you don't need getters and setters. If you think you do, you probably want property instead.
(2) Don't use __ names. They're a hack that doesn't really make things private, and doesn't even avoid name collisions all the time. There are probably a few cases where they're useful, but this is not one of them. If you don't want attributes to show up in automatically generated documentation, simply prefix them with a single underscore.
(3) Don't use class-level attributes as defaults for instance-level attributes. If it's part of the instance, set it on the instance. If it's part of the class, set it on the class. Hiding a class-level attribute with an instance-level attribute will most likely lead to confusion unless you *really* know what you're doing in Python.
Something like this would probably be best:
py> class BaseClass(object): ... def __init__(self, something='Dumb!'): ... self._something = something ... def _getsomething(self): ... return self._something ... something = property(_getsomething) ... py> class SubClass(BaseClass): ... def _setsomething(self, something): ... self._something = something ... something = property(BaseClass._getsomething, _setsomething) ... py> b = BaseClass() py> b.something 'Dumb!' py> b.something = 1 Traceback (most recent call last): File "<interactive input>", line 1, in ? AttributeError: can't set attribute py> s = SubClass() py> s.something 'Dumb!' py> s.something = 'Cool!' py> s.something 'Cool!'
STeVe -- http://mail.python.org/mailman/listinfo/python-list
