 # Python Program to Calculate the Value of nPr

In the previous article, we have discussed Python Program to Find the Number of Weeks between two Dates
nPr:

nPr indicates n permutation r.

The process of organizing all the individuals in a given set to form a sequence is referred to as permutation.

The Given mathematical formula for nPr =n!/(n-r)!

Given the values of n, r and the task is to find the value of nPr .

Examples:

Example1:

Input:

Given n value = 5
Given r value = 4

Output:

The value of nPr for above given n, r values =  120

Example 2:

Input:

Given n value = 6
Given r value = 3

Output:

The value of nPr for above given n, r values = 120

## Program to Calculate the Value of nPr

Below are the ways to calculate the value of nPr for given values of n,r.

### Method #1: Using math Module (Static Input)

Approach:

• Import math module using the import keyword.
• Give the number as static input and store it in a variable.
• Give another number as static input and store it in another variable.
• Calculate the value of nPr with reference to the standard mathematical formula n!/(n-r)! using factorial() function
• Store it in a variable.
• Print the value of nPr for the above-given n, r values.
• The Exit of the Program.

Below is the implementation:

# Import math module using the import keyword.
import math
# Give the number as static input and store it in a variable.
gvn_n_val = 5
# Give another number as static input and store it in another variable.
gvn_r_val = 4
# Calculate the value of nPr with reference to standard mathematical formula n!/(n-r)!
# using factorial() function
# Store it in a variable.
n_p_r = math.factorial(gvn_n_val)//math.factorial(gvn_n_val-gvn_r_val)
# Print the value of nPr for the above given n, r values.
print("The value of nPr for above given n, r values = ", n_p_r)


Output:

The value of nPr for above given n, r values =  120

### Method #2: Using math Module (User input)

Approach:

• Import math module using the import keyword.
• Give the number as User input using the int(input()) function and store it in a variable.
• Give another number as User input using the int(input()) function and store it in another variable.
• Calculate the value of nPr with reference to the standard mathematical formula n!/(n-r)! using factorial() function
• Store it in a variable.
• Print the value of nPr for the above-given n, r values.
• The Exit of the Program.

Below is the implementation:

# Import math module using the import keyword.
import math
# Give the number as user input using the int(input()) function and store it in a variable.
gvn_n_val = int(input("Enter some Random number = "))
# Give another number as user input using the int(input()) function and store it in another variable.
gvn_r_val = int(input("Enter some Random number = "))
# Calculate the value of nPr with reference to standard mathematical formula n!/(n-r)!
# using factorial() function
# Store it in a variable.
n_p_r = math.factorial(gvn_n_val)//math.factorial(gvn_n_val-gvn_r_val)
# Print the value of nPr for the above given n, r values.
print("The value of nPr for above given n, r values = ", n_p_r)


Output:

Enter some Random number = 6
Enter some Random number = 3
The value of nPr for above given n, r values = 120

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