Math module in Python contains a number of mathematical operations, which can be performed with ease using the module. math.comb() method in Python is used to get the number of ways to choose k items from n items without repetition and without order. It basically evaluates to n! / (k! * (n – k)!) when k n. It is also known as binomial coefficient because it is equivalent to the coefficient of k-th term in polynomial expansion of the expression (1 + x)n.
This method is new in Python version 3.8.
Syntax: math.comb(n, k)
Parameters:
n: A non-negative integer
k: A non-negative integerReturns: an integer value which represents the number of ways to choose k items from n items without repetition and without order.
Code #1: Use of math.comb() method
# Python Program to explain math.comb() method # Importing math moduleimport math n = 10k = 2 # Get the number of ways to choose# k items from n items without# repetition and without ordernCk = math.comb(n, k)print(nCk) n = 5k = 3 # Get the number of ways to choose# k items from n items without# repetition and without ordernCk = math.comb(n, k)print(nCk) |
45 10
Code #2: When k > n
# Python Program to explain math.comb() method # Importing math moduleimport math # When k > n # math.comb(n, k) returns 0.n = 3k = 5 # Get the number of ways to choose# k items from n items without# repetition and without ordernCk = math.comb(n, k)print(nCk) |
0
Code #3: Use of math.comb() method to find coefficient of k-th term in binomial expansion of expression (1 + x)n
# Python Program to explain math.comb() method # Importing math moduleimport math n = 5k = 2 # Find the coefficient of k-th# term in the expansion of # expression (1 + x)^nnCk = math.comb(n, k)print(nCk) n = 8k = 3 # Find the coefficient of k-th# term in the expansion of # expression (1 + x)^nnCk = math.comb(n, k)print(nCk) |
10 56
Reference: Python math library
