 # How to Find Factorial of Any Number in Python

This article is about finding factorial of any number in Python. In mathematics, a factorial is a positive number and represented as n!. A factorial is a product of all positive integers less than or equal to n.

For example, if we calculate the factorial of 3, then the product of all integers less than 6 will be 3*2*1 = 6. It means the factorial of 3 is 6.

Now, let's implements it using the Python program.

## Algorithm To Find Factorial in Python

Step 1: Take a number

Step 2: Check whether the number is greater than 1

Step 3: Iterate a loop for all the values less than the number

Step 4: Calculate factorial

Step 5: Repeat step 3 and 4 until the loop exits

Step 6: Display factorial

This algorithm is to calculate the factorial without using math.factorial() method. You can see its implementation in example2 below.

## Python Program to Find Factorial of Given Number using math.factorial() Method

Python provides a math module that contains the factorial() method. We can use this method to calculate factorial for any number as we did in the below code example.

``````import math
# Take a number
num = 5
print(num)
fact = 1
# Find factorial
fact = math.factorial(num)
# Display result
print("Factorial is: ",fact)``````

Output:

5

Factorial is:  120

## Python Program to Find Factorial of Given Number

In this example, we are using for loop to calculate the factorial of a number. We can use this code if don't want to use math.factorial() method. See the code and output.

``````# Take a number
num = 5
print(num)
fact = 1
# Find factorial
if num >= 1:
for i in range (1, num+1):
fact = fact * i
# Display result
print("Factorial is: ",fact)``````

Output:

5

Factorial is:  120

## Python Program to Find Factorial of Given Number using Recursion.

Recursion is a technique in which a function calls itself until the base condition. Here, we used the recursion approach to find a factorial of a number in Python. See the code and output.

``````# Take a number
num = 5
print(num)
fact = 1
# Find factorial
def factorial(num):
if num < 2:
return 1
else:
return num * factorial(num-1)
# Display result
print("Factorial is: ",factorial(num))``````

Output:

5

Factorial is:  120

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