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# 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 modulefrom scipy.special import factorial    print(factorial(3))  # False always return float valueprint(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 modulefrom scipy.special import factorial    # True always return int valueprint(factorial(4, exact=True))

Output :

24

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

## Python3

 # importing modulefrom 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 moduleimport numpy as npfrom scipy.special import factorial  # creating listlist = [6, 3, 4, 5]  # creating NumPy Arrayarr = np.array(list)  # computing factorial and displayprint("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]

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