Python | Repeat and Multiply list extension
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)) |
The original list is : [4, 5, 6] List after extension and multiplication : [4, 5, 6, 12, 15, 18, 36, 45, 54, 108, 135, 162]