Can you explain recursion in Python?

Can you explain recursion in Python?

Sure! Recursion is a programming technique where a function calls itself to solve a problem.

Can you give me an example of a recursive function?

Absolutely! A classic example is the factorial function. Here's how it looks in Python:

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n - 1)

What happens if I call factorial with a negative number?

Good question! If you call factorial(-1), it will result in a maximum recursion depth exceeded error because there’s no base case for negative numbers.

How can I prevent that error?

You can add a check at the beginning of the function to handle negative inputs, like this:

def factorial(n):
    if n < 0:
        return 'Error: Negative input not allowed'
    elif n == 0:
        return 1
    else:
        return n * factorial(n - 1)