Python

None, True, and False
integers, long integers, floating point numbers, complex numbers
normal and Unicode strings
tuples, lists, sets, and dictionaries containing only picklable objects
functions defined at the top level of a module
built-in functions defined at the top level of a module
classes that are defined at the top level of a module
instances of such classes whose __dict__ or the result of calling __getstate__() is picklable (see section The pickle protocol for details).

#!/usr/bin/python

import cPickle

f = open('temp.pkl', 'wb');

l = range(10);

cPickle.dump(l, f, 0); #default, ASCII protocol
#cPickle.dump(l, f, 1); #old binary format
#cPickle.dump(l, f, 2); #efficient pickling of new-style classes
#cPickle.dump(l, f, -1); #highest available protocol

f.close();

#!/usr/bin/python

import cPickle

f = open('temp.pkl', 'rb');

l = cPickle.load(f);

print l;

f.close();

#!/usr/bin/python

import cPickle

l = range(10);

s = cPickle.dumps(l);

t = cPickle.loads(s);
print t;

__getstate__, if the class defines the method __getstate__(), it is called and the return state is pickled as the contents for the instance, if there is no __getstate__() method, the instance's __dict__ is pickled

__setstate__, if the class also defines the method __setstate__(), it is called with the unpickled state, if there is no __setstate__() method, the pickled state must be a dictionary and its items are assigned to the new instance's dictionary

#!/usr/bin/python

class Vehicle(object):

    def __init__(self, brand):
        self.__brand = brand

    def __str__(self):
        return "Brand: %s" % self.__brand

    def __getstate__(self):
        print('Call __getstate__ for pickling ...')
        state = self.__dict__.copy()
        # Remove the unpicklable entries.
        #del state['file']
        return state

    def __setstate__(self, state):
        # Restore instance attributes
        print('Call __setstate__ for unpickling ...')
        self.__dict__.update(state)
        #self.__dict

def main():
    v = Vehicle("Buick")

    import cPickle

    # pickling
    f = open('temp.pkl', 'wb');
    cPickle.dump(v, f, 0);
    f.close();

    # unpickling
    f = open('temp.pkl', 'rb');
    l = cPickle.load(f);
    print(l);
    f.close();

    v2 = [Vehicle("Buick"), Vehicle("Honda")]

    # pickling
    f = open('temp.pkl', 'wb');
    cPickle.dump(v2, f, 0);
    f.close();

    # unpickling
    f = open('temp.pkl', 'rb');
    l = cPickle.load(f);
    for e in l:
        print(e)
    f.close();

if __name__ == '__main__':
    main()

#!/usr/bin/python
class MyRange:
    def __init__(self, start, stop, step):
        self.__sequence = range(start, stop, step);
 
    def __str__(self):
        s = '[';
        for i in self.__sequence:
            s = s + ' ' + str(i)

        return s + ' ]'

    def __getstate__(self):
        print('Call __getstate__ for pickling ...')
        state = self.__dict__.copy()
        print(state)
        # Remove the unpicklable entries.
        #del state['file']
        return state

    def __setstate__(self, state):
        # Restore instance attributes
        print('Call __setstate__ for unpickling ...')
        self.__dict__.update(state)

def main():
    l = MyRange(0, 10, 1);

    import cPickle

    # pickling
    f = open('temp.pkl', 'wb');
    cPickle.dump(l, f, 0);
    f.close();

    # unpickling
    f = open('temp.pkl', 'rb');
    l = cPickle.load(f);
    print(l);
    f.close();

if __name__ == '__main__':
    main();