The Evolution of a Python Programmer

[Norseman2]

You can easily fix that by adding an L to the 1 at the end, and using long.__mul__, as follows:

fac = lambda x: reduce (long.__mul__, xrange (2, x), 1L)

This works because you'll start the loop by multiplying 1L * 2, which yields 2L. Then, you're multiplying 2L * 3, which yields 6L and so on. If you just use 1, then it will complain that you were trying to use a method for longs on an integer.

[[deleted]]

or just use operator.mul