Sheldon wrote:
> MRAB wrote:
> > Sheldon wrote:
> > > Hi.
> > >
> > > Does anyone know if one can resume a python script at the error point
> > > after the error is corrected?
> > > I have a large program that take forever if I have to restart from
> > > scratch everytime. The error was the data writing a file so it seemed
> > > such a waste if all the data was lost and must be recalculated again.
> > >
> > You could modify the program while you're debugging it so that instead
> > of, say:
> >
> > calculate data
> > write data
> >
> > you have:
> >
> > if saved data exists:
> > load data
> > else:
> > calculate data
> > save data
> > write data
> >
> > The pickle module would be useful here.
> >
> > Matthew
>
> I like your idea Matthew but I don't know how to pickle the many
> variables in one file. Do I need to pickle each and every variable into
> a seperate file?
> var1,var2
> pickle.dump(var1,f)
> pickle.dump(var2,f2)
>
Using the 'pickle' module:
# To store:
f = open(file_path, "wb")
pickle.dump(var1, f)
pickle.dump(var2, f)
f.close()
# To load
f = open(file_path, "rb")
var1 = pickle.load(f)
var2 = pickle.load(f)
f.close()
A more flexible alternative is to use the 'shelve' module. This behaves
like a dict:
# To store
s = shelve.open(file_path)
s["var1"] = "first"
s["var2"] = [2, 3]
s.close()
# To load
s = shelve.open(file_path)
print s["var1"] # This prints "first"
print s["var2"] # This prints [2, 3]
s.close()
Hope that helps
Matthew
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