Save/Store whole class (or another object) in a file

[alexLIGO]

Hi,

is it possible in python (with/without matplotlib, numpy etc) to store
a whole class with its data into a file, instead it to reconstruct
every time again? So is there an analogous to the matlab functions
load/save available?

Thanks
Alex

 

[Sybren Stuvel]

(e-mail address removed) enlightened us with:

is it possible in python (with/without matplotlib, numpy etc) to
store a whole class with its data into a file

Check out the pickle module.

Sybren

 

[Matimus]

is it possible in python (with/without matplotlib, numpy etc) to store

a whole class with its data into a file, instead it to reconstruct
every time again? So is there an analogous to the matlab functions
load/save available?

look up the pickle module.

 

[alexLIGO]

Hi,

thanks for the reply,but unfortunately this does not work with the type
of classes I am dealing with. When trying to pickle the class I get the
following error:

File "/usr/lib/python2.4/copy_reg.py", line 76, in _reduce_ex
raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__
cannot be pickled

So there is something missing in this class? Or any other idea how to
do this?

Alex

 

[Fredrik Lundh]

thanks for the reply,but unfortunately this does not work with the type
of classes I am dealing with. When trying to pickle the class I get the
following error:

File "/usr/lib/python2.4/copy_reg.py", line 76, in _reduce_ex
raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__
cannot be pickled

So there is something missing in this class?

did you remember to read the error message before posting ?

</F>

 

[Michele Simionato]

Hi,

thanks for the reply,but unfortunately this does not work with the type
of classes I am dealing with. When trying to pickle the class I get the
following error:

File "/usr/lib/python2.4/copy_reg.py", line 76, in _reduce_ex
raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__
cannot be pickled

So there is something missing in this class? Or any other idea how to
do this?

Alex

yes, read the documentation:
http://docs.python.org/dev/lib/pickle-inst.html

Michele Simionato

 

[alexLIGO]

Hi,

did you remember to read the error message before posting ?

of course I read the error-message, I understand the error-message, BUT
this message is not telling me how anyway to save the data of such a
class in a file! It does not tell me, that there is absolutely no way
to do that. Maybe there is, maybe there is not.
Thats why I am posting it here!

Alex

 

[Gabriel Genellina]

of course I read the error-message, I understand the error-message, BUT
this message is not telling me how anyway to save the data of such a
class in a file! It does not tell me, that there is absolutely no way
to do that. Maybe there is, maybe there is not.
Thats why I am posting it here!

"A man who wears a hat without buying a ticket cannot enter the theatre"
You wear a hat, you want to enter: either buy your ticket or forget
about your hat.
In this case, just define a __getstate__ method (read the pickle
docs), or forget about __slots__.


--
Gabriel Genellina
Softlab SRL

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