gerardob a écrit :
I have a problem using Pickle inside a class object.
The following code works:
m2 = markov_model.MarkovModel()
m2 = pickle.load(open("prueba", 'rb'))
Given the second line, the first is totally useless.
print m2.n
However, if I create the following method inside markov_model.MarkovModel:
def load_model_from_file(self, name):
try:
file = open(name, 'rb')
self = pickle.load(file)
This doesn't work - or, more exactly, this doesn't work the way you
expect it to work !-)
Remember that there's nothing magical with 'self' - it's just a local
name in a function. Rebinding it within the function's body only affects
the function's local namespace.
What you want is to make load_model_from_file a classmethod and make it
return the unpickled object instead.
file.close()
except pickle.PicklingError:
print "PicklingError"
Useless exception handling - you lose all the relevant informations.
and then run:
m2 = markov_model.MarkovModel()
m2.load_model_from_file("prueba")
print m2.n
it says that 'MarkovModel' object has no attribute 'n'. If the printing of
'n' i put it inside (at the end) of the method load_model_from_file as
'print self.n' it works.
Indeed - at this stage, the *local* 'self' name has been rebound to the
unpickled object.
Also and fwiw, if you expect a MarkovModel instance to have a 'n'
attribute, you should bind it (at least to a sensible default value) in
the class __init__ method.
How can i solve this?
cf above.
HTH
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