Pickle - Python object serialization

This document describes both Pickle and cPickle modules. Pickle allows you to subclass Pickler() and Unpickler() classes, cPickle does not but is much faster (up to 1000x).

dump(obj, file[, protocol]) and load(file)

# example from Python LibRef
data1 = {'a': [1, 2.0, 3, 4+6j],
         'b': ('string', u'Unicode string'),
         'c': None}

selfref_list = [1, 2, 3]
selfref_list.append(selfref_list)

output = open('data.pkl', 'wb')

# Pickle dictionary using protocol 0.
pickle.dump(data1, output)

# Pickle the list using the highest protocol available.
pickle.dump(selfref_list, output, -1)

output.close()


# READ OUR PICKLE

import pprint

pkl_file = open('data.pkl', 'rb')

data1 = pickle.load(pkl_file)
pprint.pprint(data1)

pkl_file.close()

dumps(obj, [, protocol]) and loads(string) - Return the pickled representation of the object as a string, instead of writing it to a file, load object from a string.

# example from Python LibRef
obj = {'a':1,'b':2,'c':3}
from pickle import *
dumps(obj)
# "(dp0\nS'a'\np1\nI1\nsS'c'\np2\nI3\nsS'b'\np3\nI2\ns."