A demonstration of the difference between a regular (unordered) dictionary and collections.OrderedDict

dict_test.py

#!/usr/bin/env python

# A demonstration of the difference between a regular (unordered) dictionary
# and collections.OrderedDict

# See http://docs.python.org/library/collections.html#collections.OrderedDict
from collections import OrderedDict

def unordered_dict(dict_type):
    d = dict_type()

    for i in range(26):
        d[chr(ord('a') + i)] = i

    return d

print '*** dict ***'

for key in unordered_dict(dict).items():
    print key

print '*** OrderedDict ***'

for key in unordered_dict(OrderedDict).items():
    print key

output.txt

marca@ladyproud-lm:~/python$ ./dict_test.py 
*** dict ***
('a', 0)
('c', 2)
('b', 1)
('e', 4)
('d', 3)
('g', 6)
('f', 5)
('i', 8)
('h', 7)
('k', 10)
('j', 9)
('m', 12)
('l', 11)
('o', 14)
('n', 13)
('q', 16)
('p', 15)
('s', 18)
('r', 17)
('u', 20)
('t', 19)
('w', 22)
('v', 21)
('y', 24)
('x', 23)
('z', 25)
*** OrderedDict ***
('a', 0)
('b', 1)
('c', 2)
('d', 3)
('e', 4)
('f', 5)
('g', 6)
('h', 7)
('i', 8)
('j', 9)
('k', 10)
('l', 11)
('m', 12)
('n', 13)
('o', 14)
('p', 15)
('q', 16)
('r', 17)
('s', 18)
('t', 19)
('u', 20)
('v', 21)
('w', 22)
('x', 23)
('y', 24)
('z', 25)