Python math.factorial() - Factorial Function
Python math.factorial()
math.factorial(x) function returns the factorial of x as an integer.
Syntax
The syntax to call factorial() function is
math.factorial(x)
where
Parameter | Required | Description |
---|---|---|
x | Yes | An integer value. x >= 0. |
Note: Since Python v3.9, factorial() does not accept floats with integral values like 5.0
.
If x is not integral value, then factorial(x) raises ValueError.
Examples
1. Find factorial of integer
In the following program, we shall read an integer from user, and find its factorial.
Python Program
import math
x = int(input('Enter an integer : '))
result = math.factorial(x)
print('Factorial :', result)
Output #1
Enter an integer : 5
Factorial : 120
Output #2
Enter an integer : 0
Factorial : 1
Output #3
Enter an integer : -4
Traceback (most recent call last):
File "/Users/pe/Desktop/Projects/Python/example.py", line 4, in <module>
result = math.factorial(x)
ValueError: factorial() not defined for negative values
2. Find factorial of integer online
You can run the following program online and find the factorial of a number.
Python Program
import math
x = 7
result = math.factorial(x)
print('Factorial :', result)
Summary
In this Python Math tutorial, we learned the syntax of, and examples for math.factorial() function.