Python | i^k Summation in list

Python being the language of magicians can be used to perform many tedious and repetitive tasks in a easy and concise manner and having the knowledge to utilize this tool to the fullest is always useful. One such small application can be finding sum of i^k of list in just one line. Let’s discuss certain ways in which this can be performed.

Method #1 : Using reduce() + lambda + pow()
The power of lambda functions to perform lengthy tasks in just one line, allows it combined with reduce which is used to accumulate the subproblem, to perform this task as well. The pow() is used to perform task of computing power. Works with only Python 2.

# Python code to demonstrate  
# i ^ k Summation in list 
# using reduce() + lambda + pow() 
  
# initializing list 
test_list = [3, 5, 7, 9, 11] 
  
# printing original list  
print ("The original list is : " + str(test_list)) 
  
# initializing K  
K = 4
  
# using reduce() + lambda + pow() 
# i ^ k Summation in list 
res = reduce(lambda i, j: i + pow(j, K), [pow(test_list[:1][0], K)] + test_list[1:]) 
  
# printing result 
print ("The sum of i ^ k of list is : " + str(res)) 

Output :

The original list is : [3, 5, 7, 9, 11]
The sum of i^k of list is : 24309

Method #2 : Using map() + sum() + pow()
The similar solution can also be obtained using the map function to integrate and sum function to perform the summation of the i^k number.

# Python3 code to demonstrate  
# i ^ k Summation in list 
# using map() + sum() + pow() 
  
# initializing list 
test_list = [3, 5, 7, 9, 11] 
  
# printing original list  
print ("The original list is : " + str(test_list)) 
  
# initializing K  
K = 4
  
# using map() + sum() + pow() 
# i ^ k Summation in list 
res = sum(map(lambda i : pow(i, K), test_list)) 
  
# printing result 
print ("The sum of i ^ k of list is : " + str(res)) 

Output :

The original list is : [3, 5, 7, 9, 11]
The sum of i^k of list is : 24309

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