Python Program to repeat elements at custom indices

When it is required to repeat elements at custom indices, a simple iteration, enumerate attribute, the ‘extend’ method and the ‘append’ method are used.

Below is a demonstration of the same −

Example

my_list = [34, 56, 77, 23, 31, 29, 62, 99]
print("The list is :")
print(my_list)
index_list = [3, 1, 4, 6]
my_result = []
for index, element in enumerate(my_list):
   if index in index_list:
      my_result.extend([element, element])
   else :
      my_result.append(element)
print("The result is :")
print(my_result)

Output

The list is :
[34, 56, 77, 23, 31, 29, 62, 99]
The result is :
[34, 56, 56, 77, 23, 23, 31, 31, 29, 62, 62, 99]

Explanation

• A list is defined and displayed on the console.

• Another list of integers is defined.

• An empty list is defined.

• The list is iterated over and enumerate attribute is used, and the elements of the list are compared with the integer list.

• If an element is present in the integer list, it is added to the empty list in element’s index using ‘extend’ method.

• Otherwise, it is added to empty list using ‘append’ method.

• This is the output that is displayed on the console.