gagsl-py2 at yahoo
Nov 18, 2007, 9:20 AM
Post #3 of 3
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En Sat, 17 Nov 2007 19:30:04 -0300, Nick Craig-Wood <nick[at]craig-wood.com>
escribi�:
>> I'm working on an application that is very memory intensive, so we're
>> trying to reduce the memory footprint of classes wherever possible. I
>
> I'd guess that if you __slot__-ed the Domain class then you'll find
> the overhead of a type attribute is minimal (4 bytes per instance I
> think).
>
> No idea about Hessian or Stomp (never heard of them!) but classes with
> __slot__s are normal classes which would pickle or unpickle.
Actually classes with __slots__ require that you write your own
__getstate__ and __setstate__. The following implementation may be enough
in simple cases:
py> class X(object):
... __slots__ = ('foo','bar')
...
py> x = X()
py> x.foo = 123
py> dumps(x)
Traceback (most recent call last):
...
TypeError: a class that defines __slots__ without defining __getstate__
cannot b
e pickled
class X(object):
__slots__ = ('foo','bar')
def __getstate__(self):
return dict((name, getattr(self, name))
for name in self.__slots__
if hasattr(self, name))
def __setstate__(self, state):
for name,value in state.iteritems():
setattr(self, name, value)
py> x = X()
py> x.foo = 123
py> p = dumps(x)
py> x2 = loads(p)
py> type(x2)
<class '__main__.X'>
py> x2.foo
123
py> x2.bar
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: bar
--
Gabriel Genellina
--
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