On Mon, 20 Aug 2012 21:17:15 -0700 (PDT), Massimo Di Pierro
<massimo.dipie...@gmail.com> wrote:
Consider this code:
class SlowStorage(dict):
def __getattr__(self,key):
return self[key]
def __setattr__(self,key):
self[key]=value
class FastStorage(dict):
def __init__(self, __d__=None, **kwargs):
self.update(__d__,**kwargs)
def __getitem__(self,key):
return self.__dict__.get(key,None)
def __setitem__(self,key,value):
self.__dict__[key] = value
def __delitem__(self,key):
delattr(self,key)
def __copy__(self):
return Storage(self)
def __nonzero__(self):
return len(self.__dict__)>0
def pop(self,key,default=None):
if key in self:
default = getattr(self,key)
delattr(self,key)
return default
def clear(self):
self.__dict__.clear()
def __repr__(self):
return repr(self.__dict__)
def keys(self):
return self.__dict__.keys()
def values(self):
return self.__dict__.values()
def items(self):
return self.__dict__.items()
def iterkeys(self):
return self.__dict__.iterkeys()
def itervalues(self):
return self.__dict__.itervalues()
def iteritems(self):
return self.__dict__.iteritems()
def viewkeys(self):
return self.__dict__.viewkeys()
def viewvalues(self):
return self.__dict__.viewvalues()
def viewitems(self):
return self.__dict__.viewitems()
def fromkeys(self,S,v=None):
return self.__dict__.fromkeys(S,v)
def setdefault(self, key, default=None):
try:
return getattr(self,key)
except AttributeError:
setattr(self,key,default)
return default
def clear(self):
self.__dict__.clear()
def len(self):
return len(self.__dict__)
def __iter__(self):
return self.__dict__.__iter__()
def has_key(self,key):
return key in self.__dict__
def __contains__(self,key):
return key in self.__dict__
def update(self,__d__=None,**kwargs):
if __d__:
for key in __d__:
kwargs[key] = __d__[key]
self.__dict__.update(**kwargs)
def get(self,key,default=None):
return getattr(self,key) if key in self else default
>>> s=SlowStorage()
>>> a.x=1 ### (1)
>>> a.x ### (2)
1 # ok
>>> isinstance(a,dict)
True # ok
>>> print dict(a)
{'x':1} # ok (3)
Try:
a.items()
What does that show?
>>> s=FastStorage()
>>> a.x=1 ### (4)
>>> a.x ### (5)
1 # ok
>>> isinstance(a,dict)
True # ok
>>> print dict(a)
{} # not ok (6)
Lines (4) and (5) are about 10x faster then lines (1) and (2). I
like
FastStorage better but while (3) behaves ok, (6) does not behave as
I
want.
I intuitively understand why FastStorage is cannot cast into dict
properly.
What I do not know is how to make it do the casting properly without
losing the 10x speedup of FastStorage over SlowStorage.
Any idea?
I don't really understand what your trying to do but since you didn't
add the __setattr__ method to FastStorage the item is not added to
the dictionary when you do a.x = 1
Oscar
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