Reversing a number into a list

Leveraging the power of the lambda function, we can apply a “headless function” to an iterable item. Lets look at this simple example:

Given a non-negative integer, return an array containing a list of independent digits in reverse order.

def digitize(n):
    n = str(n)[::-1]
    return map(lambda x: int(x), [x for x in n])

Our utilization of the lambda function, in conjunction with some python list expansion, has circumvented the need for other more complex looping mechanisms. Although lambda functions may seem scare in practice, they are useful to have in your tool-belt to craft a more elegant solution to a problem.