How to find the factorial os a number using SciPy in Python?

 SciPy is an open-source Python library used to solve scientific and mathematical problems. It is built on NumPy and it allows us to manipulate and visualizing with a wide range of high-level commands. Scipy also provides a scipy.special.factorial() function to calculate factorial of any number.

scipy.special.factorial()

This function takes two parameters, int or array_like of int another Boolean and return the factorial of the given parameter as integer or float depending on boolean.

Syntax: scipy.special.factorial(n, exact=False)

Parameters:  

n : int or array_like of ints 

exact : bool, optional 

Returns:  

nf : float or int or ndarray (Output depending on exact).  

Note: If Exact is True return integer value and if False it returns floating values with using the gamma function and default is False.

Example 1:

Python3

# importing module
from scipy.special import factorial


print(factorial(3))

# False always return float value
print(factorial(4, exact=False))

Output :

6.0
24.0

Example 2: If exact value is True then it returns always an integer value.

Python3

# importing module
from scipy.special import factorial


# True always return int value
print(factorial(4, exact=True))

Output :

24

Example 3: If we compute the negative value for factorial then it always returns zero.

Python3

# importing module
from scipy.special import factorial


print(factorial(-3, exact=False))
print(factorial(-4, exact=True))

Output :

0.0
0

Example 4: Get factorial for the array element.

Python3

# importing module
import numpy as np
from scipy.special import factorial

# creating list
list = [6, 3, 4, 5]

# creating NumPy Array
arr = np.array(list)

# computing factorial and display
print("Factorial value in float : ",
      factorial(arr, exact=0))

print("Factorial value in Integer : ",
      factorial(arr, exact=1))

Output :

Factorial value in float :  [720.   6.  24. 120.]
Factorial value in Integer :  [720   6  24 120]