Anonymous functions

One last type of functions that I want to talk about are anonymous functions. These functions, which are called lambdas in Python, are usually used when a fully-fledged function with its own name would be overkill, and all we want is a quick, simple one-liner that does the job.

Imagine that you want a list of all the numbers up to N which are multiples of five. Imagine that you want to filter those out using the filter function, which takes a function and an iterable and constructs a filter object which you can iterate on, from those elements of iterable for which the function returns True. Without using an anonymous function, you would do something like this:

filter.regular.py

def is_multiple_of_five(n):
    return not n % 5
def get_multiples_of_five(n):
    return list(filter(is_multiple_of_five, range(n)))
print(get_multiples_of_five(50))

I have highlighted the main logic of get_multiples_of_five. Note how the filter uses is_multiple_of_five to filter the first n natural...