Factorial

OSCC · Python, Math, Recursion · Sep 15, 2020

Calculates the factorial of a number.

  • Use recursion.
  • If num is less than or equal to 1, return 1.
  • Otherwise, return the product of num and the factorial of num - 1.
  • Throws an exception if num is a negative or a floating point number.
def factorial(num):
  if not ((num >= 0) and (num % 1 == 0)):
    raise Exception("Number can't be floating point or negative.")
  return 1 if num == 0 else num * factorial(num - 1)
factorial(6) # 720

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