Re: Save and load initialized class

[Bob van der Poel]

Yes, all cool. But,

   json.dump(Opts.__dict__, open("mybuffer", "w"))

still doesn't work with python3. Returns "is not JSON serializable"

On Sun, Dec 10, 2017 at 4:00 AM, Steve D'Aprano 
wrote:

> On Sun, 10 Dec 2017 04:52 am, MRAB wrote:
>
> > Try updating __dict__:
> >
> >  Opts.__dict__.update(json.load(open("mybuffer")))
>
> __dict__ is implementation, vars() is the public interface:
>
> vars(Opts).update(json.load(open("mybuffer")))
>
>
> Looks nicer too :-)
>
>
>
>
> --
> Steve
> “Cheer up,” they said, “things could be worse.” So I cheered up, and sure
> enough, things got worse.
>
> --
> https://mail.python.org/mailman/listinfo/python-list
>



-- 

 Listen to my FREE CD at http://www.mellowood.ca/music/cedars 
Bob van der Poel ** Wynndel, British Columbia, CANADA **
EMAIL: b...@mellowood.ca
WWW:   http://www.mellowood.ca
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Re: Save and load initialized class

[Steve D'Aprano]

On Sun, 10 Dec 2017 04:52 am, MRAB wrote:

> Try updating __dict__:
> 
>  Opts.__dict__.update(json.load(open("mybuffer")))

__dict__ is implementation, vars() is the public interface:

vars(Opts).update(json.load(open("mybuffer")))


Looks nicer too :-)




-- 
Steve
“Cheer up,” they said, “things could be worse.” So I cheered up, and sure
enough, things got worse.

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Re: Save and load initialized class

[MRAB]

On 2017-12-08 18:36, Bob van der Poel wrote:

I'm trying to something simple (yeah, right). Mainly I want to have a bunch
of variables which my program needs and uses to be in a saveable/loadable
block. Currently I have then all as a bunch of globals which works, but
trying to keep track of them and the correct spellings, etc becomes a bit
of maintenance nightmare. So, demonstrating all my cleverness I came up
with:

class Opts():
  var1 = 123
  var2 = "hello world"

Notationally, it looks much like the variables are stored in a separate
module. I can call these options from within a function with the simple
notation:

   if Opts.var1 == 99 ...

And, if I need to change a value I can:

  global
  Opts.var1 = 0

Further, and importantly, I can save the lot with:

   json.dump(Opts.__dict__, open("mybuffer", "w"))

But, I can't figure out how to load the saved data back into my program.
Doing

   z=json.load (open("mybuffer", "r"))

loads a dictionary ... which makes sense since that is what I saved. So,
can I now reset the values in Opts from a saved dictionary?


Try updating __dict__:

Opts.__dict__.update(json.load(open("mybuffer")))
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Re: Save and load initialized class

[dieter]

Bob van der Poel  writes:

> I'm trying to something simple (yeah, right). Mainly I want to have a bunch
> of variables which my program needs and uses to be in a saveable/loadable
> block. Currently I have then all as a bunch of globals which works, but
> trying to keep track of them and the correct spellings, etc becomes a bit
> of maintenance nightmare. So, demonstrating all my cleverness I came up
> with:
>
> class Opts():
>  var1 = 123
>  var2 = "hello world"
> 
> Further, and importantly, I can save the lot with:
>
>   json.dump(Opts.__dict__, open("mybuffer", "w"))
>
> But, I can't figure out how to load the saved data back into my program.
> Doing
>
>   z=json.load (open("mybuffer", "r"))
>
> loads a dictionary ... which makes sense since that is what I saved. So,
> can I now reset the values in Opts from a saved dictionary?

You could use:

  for k, v in z.iteritems: setattr(Opts, k, v)


Of course, this means that you already have a class "Opts" (maybe
without or with different parameter values).


This poses the question why you want to dump/load the class in the first
place. Usually, you would want to have the values in code, not stored/loaded.


If you really want make parameter values persistent, you could use
the following approach:

class ParameterCollection(object):
  def __init__(self, **kwargs):
for k, v in kwargs.iteritems(): setattr(self, k, v)

my_parameters = ParameterCollection(a=1, b=2, )

from pickle import load, dump
dump(my_parameters, open(..., "wb"), -1)
...
my_parameters_reloaded = load(open(..., "rb"))

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Save and load initialized class

[Bob van der Poel]

I'm trying to something simple (yeah, right). Mainly I want to have a bunch
of variables which my program needs and uses to be in a saveable/loadable
block. Currently I have then all as a bunch of globals which works, but
trying to keep track of them and the correct spellings, etc becomes a bit
of maintenance nightmare. So, demonstrating all my cleverness I came up
with:

class Opts():
 var1 = 123
 var2 = "hello world"

Notationally, it looks much like the variables are stored in a separate
module. I can call these options from within a function with the simple
notation:

  if Opts.var1 == 99 ...

And, if I need to change a value I can:

 global
 Opts.var1 = 0

Further, and importantly, I can save the lot with:

  json.dump(Opts.__dict__, open("mybuffer", "w"))

But, I can't figure out how to load the saved data back into my program.
Doing

  z=json.load (open("mybuffer", "r"))

loads a dictionary ... which makes sense since that is what I saved. So,
can I now reset the values in Opts from a saved dictionary?

Best,


-- 

 Listen to my FREE CD at http://www.mellowood.ca/music/cedars 
Bob van der Poel ** Wynndel, British Columbia, CANADA **
EMAIL: b...@mellowood.ca
WWW:   http://www.mellowood.ca
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