Factorial of a number in Python using recursion | Example code

To get the Factorial of a number in Python using recursion, you have to use function, if statement and recursion login.

factorial of n is

n!=n*(n-1)*....2*1

A factorial is positive integer n, and denoted by n!. Then the product of all positive integers is less than or equal to n.

Factorial of 5 is:

5! = 1*2*3*4*5 = 120.

Example find Factorial of a number in Python using recursion

Simple example code Factorial of a number using recursion.

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


num = 7

# check if the number is negative
if num < 0:
    print("Use Positive numbers")
elif num == 0:
    print("The factorial of 0 is 1")
else:
    print("The factorial of", num, "is", foo(num))

Output:

User input value

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


# taking input from the user
number = int(input("User Input : "))
print("The factorial of", number, "is", foo(number))

Output:

User Input : 5
The factorial of 5 is 120

Do comment if you have any doubts or suggestions on this Python factorial program.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.