How to initialize arrays and copy objects the right way in Python

copy.py

"""
    This brief script demonstrates a frequent mistake in Python related
    to the different ways of copying objects.
    
    References: 
    1. Personal experience 
    2. http://stackoverflow.com/questions/2196956/add-an-object-to-an-array-python
"""

import copy # http://docs.python.org/library/copy.html

def wrong_way_to_copy():
    l = [[]] * 2 # a shallow copy
    l[0].append(1)
    print l # we get [[1], [1]] - WRONG!

def right_way_to_copy():
    l = [copy.copy(x) for x in [[]] * 2] # a deep copy
    l[0].append(1)
    print l # we get [[1], []] - RIGHT!

wrong_way_to_copy()
right_way_to_copy()