THE WORLD'S LARGEST WEB DEVELOPER SITE

# Python math.perm() Method

❮ Math Methods

### Example

Find the number of ways to choose k things from n items:

# Import math Library
import math

# Initialize the number of items to choose from
n = 7

# Initialize the number of items to choose
k = 5

# Print the number of ways to choose k items from n items
print (math.perm(n, k))

The result will be:

`2520`
Run Example »

## Definition and Usage

The `math.perm()` method returns the number of ways to choose k items from n items with order and without repetition.

Note: The k parameter is optional. If we do not provide one, this method will return n! (for example, math.perm(7) will return 5040).

math.perm(n, k)

## Parameter Values

Parameter Description
n Required. Positive integers of items to choose from
k Optional. Positive integers of items to choose

Note: If k is greater than n, it returns 0.

Note: If n or k are negative, a ValueError occurs. If n or k  are not integers, a TypeError occurs.

## Technical Details

Return Value: An `int` value, representing the number of ways to choose k items from n items with order and without repetition 3.8

❮ Math Methods