Is there a way to view cPickle or Pickle file cont

Question

I use cPickle to save data sets from each run of a program. Since I sometimes need to see the outline of the data without running the code, I would like an easy way to quickly view the contents by just double-clicking on the file. I am trying to avoid having to load a terminal and pointing python to a file each time, just to run some print script.

I looked for Notepad++ plugins but couldn't find anything.

Is there some easy way to do this? Does anyone have any suggestions?

Note: I run Windows 7.

Answer 1

For Python 3.2+/2.7+ you can view (__repr__'s of) pickles from the command-line:

$ python -c "import pickle; pickle.dump({'hello': 'world'}, open('obj.dat', 'wb'))"
$ python -mpickle obj.dat
{'hello': 'world'}

It should be easy to integrate this into the Windows shell.

Answer 2

I REALLY doubt that there's any way to do this since with pickle, you can pack in pretty much anything. When unpickling, you need to be able to load the modules etc. that were loaded when the object was pickled. In other words, in general, to be able to unpickle something, python needs to be able to reproduce the "environment" of the program (or at least a close enough approximation) -- loaded modules, classes in the global namespace, etc ... In general, this isn't possible without some help from the user. Consider:

import pickle
class Foo(object): pass

a = Foo()
with open('data.pickle','wb') as f:
    pickle.dump(a,f)

Now if you try to restore this in a separate script, python has no way of knowing what a Foo looks like and so it can't restore the object (unless you define an suitable Foo object in that script). This isn't really a process that can be done without some human intervention.

Of course, an arguably useful special case where you're just pickling builtin objects and things from the standard library might be able to be attempted ... but I don't think you could write a general unpickler extension.