factorial() in Python

factorial() in Python

Not many people know, but python offers a direct function that can compute the factorial of a number without writing the whole code for computing factorial.

Naive method to compute factorial

Output :

The factorial of 23 is : 25852016738884976640000

Using math.factorial()

This method is defined in “math” module of python. Because it has C type internal implementation, it is fast.

math.factorial(x)
Parameters :
x : The number whose factorial has to be computed.
Return value :
Returns the factorial of desired number.
Exceptions : 
Raises Value error if number is negative or non-integral.

Output :

The factorial of 23 is : 25852016738884976640000

Exceptions in math.factorial()

• If give number is Negative :
  # Python code to demonstrate math.factorial() # Exceptions ( negative number )   import math   print ("The factorial of -5 is : ",end="")   # raises exception print (math.factorial(-5))

  Output :

  The factorial of -5 is : 
  

  Runtime Error :

  Traceback (most recent call last):
    File "/home/f29a45b132fac802d76b5817dfaeb137.py", line 9, in 
      print (math.factorial(-5))
  ValueError: factorial() not defined for negative values
  

• If given number is Non – Integral Value :
  # Python code to demonstrate math.factorial() # Exceptions ( Non-Integral number )   import math   print ("The factorial of 5.6 is : ",end="")   # raises exception print (math.factorial(5.6))

  Output :

  The factorial of 5.6 is : 
  

  Runtime Error :

  Traceback (most recent call last):
    File "/home/3987966b8ca9cbde2904ad47dfdec124.py", line 9, in 
      print (math.factorial(5.6))
  ValueError: factorial() only accepts integral values
  

Last Updated on October 24, 2021 by admin