Skip to content
Related Articles

Related Articles

Python | Repeat and Multiply list extension
  • Last Updated : 27 Aug, 2019

Sometimes, while working with Python list, we can have a problem in which we need to extend a list in a very customized way. We may have to repeat contents of list and while doing that, each time new list must be a multiple of original list. This incremental expansion has applications in many domains. Let’s discuss a way in which this task can be performed.

Method : Using list comprehension
This task can be performed in a brute manner, but having a shorter implementation using list comprehension always is better. In this, we perform task in 2 steps, first we make a helper list to form a multiplication factor list and then cumulate the result using original list.

# Python3 code to demonstrate working of
# Repeat and Multiply list extension
# Using list comprehension
# initializing list
test_list = [4, 5, 6]
# printing original list
print("The original list is : " + str(test_list))
# Extension factor
N = 4
# Multiply factor 
M = 3
# Repeat and Multiply list extension
# Using list comprehension
temp = [1 * M**i for i in range(N)]
res = list([ele * tele for tele in temp for ele in test_list])
# printing result 
print("List after extension and multiplication : " + str(res))
Output :
The original list is : [4, 5, 6]
List after extension and multiplication : [4, 5, 6, 12, 15, 18, 36, 45, 54, 108, 135, 162]

 Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.  

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up
Recommended Articles
Page :