Python | Multiply all numbers in the list (3 different ways)
Given a list, print the value obtained after multiplying all numbers in a list.
Examples:
Input : list1 = [1, 2, 3] Output : 6 Explanation: 1*2*3=6 Input : list1 = [3, 2, 4] Output : 24
Method 1: Traversal
Initialize the value of product to 1(not 0 as 0 multiplied with anything returns zero). Traverse till the end of the list, multiply every number with the product. The value stored in the product at the end will give you your final answer.
Below it the Python implementation of the above approach:
# Python program to multiply all values in the # list using traversal def multiplyList(myList) : # Multiply elements one by one result = 1 for x in myList: result = result * x return result # Driver code list1 = [1, 2, 3] list2 = [3, 2, 4] print(multiplyList(list1)) print(multiplyList(list2)) |
Output:
6 24
Method 2: Using numpy.prod()
We can use numpy.prod() from import numpy to get the multiplication of all the numbers in the list. It returns an integer or a float value depending on the multiplication result.
Below it the Python3 implementation of the above approach:
# Python3 program to multiply all values in the # list using numpy.prod() import numpy list1 = [1, 2, 3] list2 = [3, 2, 4] # using numpy.prod() to get the multiplications result1 = numpy.prod(list1) result2 = numpy.prod(list2) print(result1) print(result2) |
Output:
6 24
Method 3 Using lambda function: Using numpy.array
Lambda definition does not include a “return” statement, it always contains an expression which is returned. We can also put a lambda definition anywhere a function is expected, and we don’t have to assign it to a variable at all. This is the simplicity of lambda functions. The reduce() function in Python takes in a function and a list as argument. The function is called with a lambda function and a list and a new reduced result is returned. This performs a repetitive operation over the pairs of the list.
Below is the Python3 implementation of the above approach:
# Python3 program to multiply all values in the # list using lambda function and reduce() from functools import reducelist1 = [1, 2, 3] list2 = [3, 2, 4] result1 = reduce((lambda x, y: x * y), list1) result2 = reduce((lambda x, y: x * y), list2) print(result1) print(result2) |
Output:
6 24