Multiply all elements in the list of Python

In this tutorial, we will discuss how to multiply all elements in a list in Python. There are multiple ways to perform multiplication within a list. We will discuss some of them here. If you want to see our other Step By Step Python List Tutorials Click here.

Multiply all elements in a list using the Traversal method

Using the traversal method to multiply all elements in the List, we will run a for loop and traverse through the list. For loop will multiply every number by the previous number each time it iterates. For example, when the first time it iterates, it will multiply it by 1. The res is set to 1 and not 0 since every number multiplied by 0 is 0. The second time it iterates, it will multiply it with the product of 1 and the previous number, and so on.

# Code Starts here

list = [1,2,3,4,5,6,7,8]

res = 1

for i in list:
  res = res * i
  
print(res)

# code ends here

Output: 
40320

Multiply each element in a list using numpy prod

Another method is using Numpy. To Multiply All Elements In the List in Python, We will have to install NumPy first all. Then we will use a built-in function of NumPy to get the product of the list.

# Using numpy.prod Method

import numpy

list = [1,2,3,4,5,6,7,8,9]

result = numpy.prod(list)

print(result)

#Code ends here

Output: 
362880

multiply each number in a list using the lambda function

Another approach to multiplying all elements in the list in Python is using Lambda Function. Lambda’s definition does not include a “return” statement, it always contains an expression that is returned. Lambda Function can be used anywhere a function is expected. There is no need to assign it to a variable at all. This makes lambda functions simple to use. Similarly, the reduce() function in Python takes in a function and a list as an argument. This performs a repetitive operation over the pairs of the list. 

# Code starts here

from functools import reduce

list = [1, 2, 3, 4, 5, 6, 7]
 
res = reduce((lambda x, y: x * y), list))

print(res)

# Code ends here

Output:
5040

multiplication of all values in the list using math.prod

The product of a list can also be calculated using a prod function included in Math Library. Let’s see it.

#Code starts here

from functools import reduce

list = [1, 2, 3, 4, 5, 6, 7]
 
res = reduce((lambda x, y: x * y), list))

print(res)

#Code ends here

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