Core Python Programming (2nd Edition)

Core Style: Use uppercase "L" with long integers
Although Python supports a case-insensitive "L" to denote longs, we
recommend that you use only the uppercase "L" to avoid confusion
with the number one (1). Python will display only longs with a capital
"L ." As integers and longs are slowly being unified, you will only see
the "L" with evaluatable string representations (repr()) of longs.
Printable string representations (str()) will not have the "L ."
>>> aLong = 999999999l
>>> aLong
999999999L
>>> print aLong
999999999
5.2.4. Unification of Integers and Long Integers
Both integer types are in the process of being unified into a single integer type. Prior to Python 2.2,
plain integer operations resulted in overflow (i.e., greater than the 232 range of numbers described
above), but in 2.2 or after, there are no longer such errors.
Python 2.1
>>> 9999 ** 8
Traceback (most recent call last):
File "", line 1, in ?
OverflowError: integer exponentiation
Python 2.2
>>> 9999 ** 8
99920027994400699944002799920001L
Removing the error was the first phase. The next step involved bit-shifting; it used to be possible to leftshift
bits out of the picture (resulting in 0):
>>> 2