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).

cPickle has been removed in Python 3

#!/usr/bin/python
 
import pickle
 
f = open('temp.pkl', 'wb');
 
l = list(range(10))
 
pickle.dump(l, f, 0); #default, ASCII protocol
#pickle.dump(l, f, 1); #old binary format
#pickle.dump(l, f, 2); #efficient pickling of new-style classes
#pickle.dump(l, f, -1); #highest available protocol
 
f.close();

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

l = pickle.load(f);

print(l)

f.close();

#!/usr/bin/python
 
import pickle
 
l = list(range(10))
 
s = pickle.dumps(l, 2);
print(s)
 
t = pickle.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 pickle
 
    # pickling
    f = open('temp.pkl', 'wb');
    pickle.dump(v, f, 0);
    f.close();
 
    # unpickling
    f = open('temp.pkl', 'rb');
    l = pickle.load(f);
    print(l);
    f.close();
 
    v2 = [Vehicle("Buick"), Vehicle("Honda")]
 
    # pickling
    f = open('temp.pkl', 'wb');
    pickle.dump(v2, f, 0);
    f.close();
 
    # unpickling
    f = open('temp.pkl', 'rb');
    l = pickle.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 pickle
 
    # pickling
    f = open('temp.pkl', 'wb');
    pickle.dump(l, f, 0);
    f.close();
 
    # unpickling
    f = open('temp.pkl', 'rb');
    l = pickle.load(f);
    print(type(l), l);
    f.close();
 
if __name__ == '__main__':
    main();