Recursion

Recursion is the process of using a dynamically expanding equation to find a solution, rather than a traditional loop. Let’s begin with factorials as an example:

The factorial of any non-negative integer is $n!$, where $n!=n(n-1)(n-2)...(n-n)$. We can represent this with the following recursive python code:

def recursive_factorial(factor):
	if factor == 1:
	    return factor
	else:
	    return factor * recursive_factorial(factor - 1)

The first most important line of this code is:

return factor * recursive_factorial(factor - 1)