python persistence

George Sakkis george.sakkis at gmail.com
Mon Mar 31 22:27:56 EDT 2008


On Mar 31, 8:51 pm, castiro... at gmail.com wrote:
> On Mar 31, 7:14 pm, 7stud <bbxx789_0... at yahoo.com> wrote:
>
>
>
> > On Mar 31, 5:31 pm, castiro... at gmail.com wrote:
>
> > > Can you have a Python object stored entirely on disk?
>
> > import cPickle as cp
>
> > class Dog(object):
> >     def __init__(self, name):
> >         self.name = name
>
> > d = Dog("Spot")
>
> > f = open("data.txt", "w")
> > cp.dump(d, f)
> > f.close()
>
> > f = open("data.txt")
> > stored_obj = cp.load(f)
> > print stored_obj.name
>
> > --output:--
> > Spot
> >>> import pickle
> >>> pickle.loads( pickle.dumps( type('None',(),{}) ) )
>
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "C:\Programs\Python\lib\pickle.py", line 1303, in dumps
>     Pickler(f, protocol).dump(obj)
>   File "C:\Programs\Python\lib\pickle.py", line 221, in dump
>     self.save(obj)
>   File "C:\Programs\Python\lib\pickle.py", line 283, in save
>     f(self, obj) # Call unbound method with explicit self
>   File "C:\Programs\Python\lib\pickle.py", line 697, in save_global
>     (obj, module, name))
> pickle.PicklingError: Can't pickle <class '__main__.None'>: it's not
> found as __
> main__.None
>
>

http://docs.python.org/lib/node317.html



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