Python – Append List every Nth index

When it is required to append list every ‘N’th index, a simple iteration and the ‘enumerate’ attribute are used.

Example

Below is a demonstration of the same −

my_list = [13, 27, 48, 12, 21, 45, 28, 19, 63] print("The list is :") print(my_list) append_list = ['P', 'Y', 'T'] N = 3 print("The value of N is ") print(N) my_result = [] for index, element in enumerate(my_list):    if index % N == 0:       for element_in in append_list:          my_result.append(element_in)    my_result.append(element) print("The result is :") print(my_result)

Output

The list is : [13, 27, 48, 12, 21, 45, 28, 19, 63] The value of N is 3 The result is : ['P', 'Y', 'T', 13, 27, 48, 'P', 'Y', 'T', 12, 21, 45, 'P', 'Y', 'T', 28, 19, 63]

Explanation

• A list is defined and displayed on the console.

• Another integer list is defined.

• The value for N is defined and displayed on the console.

• An empty list is created.

• The list is iterated over using ‘enumerate’, and every element is divided by N and its remainder is compared to 0.

• If it is 0, the element is again checked if it is present in the integer list.

• If yes, it is appended to the empty list.

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