Python – Find Product of Index Value and find the Summation
Given a List of elements, write a Python program to perform the product of index and value and compute the summation.
Examples:
Input : test_list = [5, 3, 4, 9, 1, 2]
Output : 76
Explanation : 5 + (3*2) 6 + 12 + 36 + 5 + 12 = 76
Input : test_list = [5, 3, 4]
Output : 23
Explanation : 5 + (3*2) 6 + 12 = 23
Method #1: Using loop + enumerate()
In this, we iterate for each element along with its index using enumerate() and compute the product. Sum counter is maintained to update the intermediate sum of the product computed.
Python3
# Python3 code to demonstrate working of# Index Value Product Sum# Using loop + enumerate() # initializing listtest_list = [5, 3, 4, 9, 1, 2] # printing original listprint("The original list is : " + str(test_list)) res = 0for idx, ele in enumerate(test_list): # updating summation of required product res += (idx + 1) * ele # printing resultprint("The computed sum : " + str(res)) |
Output
The original list is : [5, 3, 4, 9, 1, 2] The computed sum : 76
Method #2 : Using sum() + list comprehension + enumerate()
One liner way to solve this problem, in this, we perform task of getting products iteration as list comprehension and summation at end is done using sum().
Python3
# Python3 code to demonstrate working of# Index Value Product Sum# Using loop + enumerate() # initializing listtest_list = [5, 3, 4, 9, 1, 2] # printing original listprint("The original list is : " + str(test_list)) # one liner to solve problem using list comprehensionres = sum([(idx + 1) * ele for idx, ele in enumerate(test_list)]) # printing resultprint("The computed sum : " + str(res)) |
Output
The original list is : [5, 3, 4, 9, 1, 2] The computed sum : 76
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