How to implement a function to cover both single and multiple values

Question

Say you have a value like this:

n = 5

and a function that returns the factorial of it, like so:

factorial(5)

How do you handle multiple values:

nums = [1,2,3,4,5]
factorial (nums)

so it returns the factorials of all these values as a list?

What's the cleanest way to handle this, without writing 2 methods? Does Python have a good way to handle these kinds of situations?

Answer 1

def Factorial(arg):
    try:
        it = iter(arg)
    except TypeError:
        pass
    else:
        return [Factorial(x) for x in it]
    return math.factorial(arg)

If it's iterable, apply recursivly. Otherwise, proceed normally.

Alternatively, you could move the last return into the except block.

If you are sure the body of Factorial will never raise TypeError, it could be simplified to:

def Factorial(arg):
    try:
        return [Factorial(x) for x in arg]
    except TypeError:
        return math.factorial(arg)