Python | Sliced Product in List

Last Updated : 29 Dec, 2019

Accessing elements in a list has many types and variations. These are an essential part of Python programming and one must know to perform the same. This article discusses ways to fetch the initial K elements and do its multiplication. Let’s discuss a certain solution to perform this task.

Method #1 : Using list slicing + loop
This problem can be performed in 1 line rather than using a loop using the list slicing functionality provided by Python and then using a loop to perform the product.

# Python3 code to demonstrate 
# Sliced Product in List
# using list slicing + loop
  
# getting Product
def prod(val) :
    res = 1 
    for ele in val:
        res *= ele
    return res 
  
# initializing list 
test_list = [4, 5, 2, 6, 7, 8, 10] 
  
# printing original list 
print("The original list : " + str(test_list)) 
  
# initializing K 
K = 5
  
# Sliced Product in List
# using list slicing + loop
res = prod(test_list[:K])
  
# print result 
print("The first K elements product of list is : " + str(res)) 

Output :

The original list : [4, 5, 2, 6, 7, 8, 10]
The first K elements product of list is : 1680

Method #2 : Using islice() + loop
The inbuilt funtions can also be used to perform this particular task. The islice function can be used to get the sliced list and then prod() can be employed to perform product.

# Python3 code to demonstrate 
# Sliced Product in List
# using islice() + loop
from itertools import islice 
  
# getting Product
def prod(val) :
    res = 1 
    for ele in val:
        res *= ele
    return res 
  
# initializing list 
test_list = [4, 5, 2, 6, 7, 8, 10] 
  
# printing original list 
print("The original list : " + str(test_list)) 
  
# initializing K 
K = 5
  
# Sliced Product in List
# using islice() + loop
res = list(islice(test_list, 0, K)) 
res = prod(res)
  
# print result 
print("The first K elements product of list is : " + str(res)) 

Output :

The original list : [4, 5, 2, 6, 7, 8, 10]
The first K elements product of list is : 1680

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