CODEWITHSUNDEEP
python
Mr.Smithyyy
Mr.Smithyyy

Reputation: 1329

Calculating factorials with Python

EDIT: I know I can import factorials but I'm doing this as an exercise

Trying to get the factor of a given number with a function in Python.

For example: factorial(4) = 4 * 3 * 2 * 1 = 24

def factorial(x):
    n = x
    while n >= 0:
        x = n * (n - 1)
        n -= 1
    return x

Upvotes: 0

Views: 5777

Answers (5)

arthur
arthur

Reputation: 21

input:

n = 10
print(str(n) + "! = ", end = '')
def factorial(n):
    '''
    print factorial number in human way
    '''
    if n < 0:
        return 'factorial() not defined for negative values'
    if n == 0:
        return 1
    if n == 1:
        print('', n, ' =', end = ' ')
        return 1
    else:
        print('', n, '*', end = '')
        return n * factorial(n - 1)

print(factorial(n))

output:

10! = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 3628800

Upvotes: 0

Kate Kiatsiri
Kate Kiatsiri

Reputation: 73

def factorial(n):
    total = 1
    for num in range(2,n+1):
        total *= num
    return total

Upvotes: 0

Alex
Alex

Reputation: 44325

I present an even shorter code for recursive factorial calculation. Not sure if it is faster or slower than other approaches:

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

fac(10)
3628800

Upvotes: 0

Gordonium
Gordonium

Reputation: 3487

A good way of approaching this would be using recursion where a function calls itself. See Function for Factorial in Python

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

But in your case your return statement actually breaks out of the while loop. So if you pass in 5 you get 20 back which is obviously not 5! (5 factorial).

Instead, try this:

def factorial(x):
   n = 1
   while x > 1:
       n *= x
       x -= 1
   return n

print (factorial(5))

But do have a go at the recursive approach.

If you really want to cheat try:

import math
math.factorial(n)

Upvotes: 1

Hackaholic
Hackaholic

Reputation: 19743

try like this: to make your code work

def factorial(x):
    n = 1   # this will store the factorial value
    while x > 0:
        n = n*x
        x -= 1
    return n

you got many advice on comments follow it

Upvotes: 4

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