How to Create a List of N-Lists in Python

In this article, we will cover how to create a list of n-lists in Python.

In Python, we can have a list of many different kinds, including strings, numbers, and more. Python also allows us to create a nested list, often known as a two-dimensional list, which is a list within a list. Here we will cover different approaches to creating a list of n-lists in Python. 

The different approaches that we will cover in this article are:

• Using simple multiplication
• Using loop
• Using List comprehension
• Using itertools

Creating a list of n-lists in Python

Example 1: Using simple multiplication 

In this example, we are multiplying the list by 4 to get a list of lists.

Python3

# Create a list with 4 references of same sub list
lis = [[]] * 4
print(lis)

Output:

[[], [], [], []]

Example 2: Using List comprehension 

In this example, we are using list comprehension for generating a list of lists.

Python3

d1 = [[] for x in range(6)]
print(d1)

Output:

[[], [], [], [], [], []]

Example 3: Using a loop

In this example, we are creating a list using a loop with a range of 6 and appending lists into a list.

Python3

list1 = []
list2 = []

for x in range(0,5):
  list1.append(list2)

print(list1)

Output:

[[], [], [], [], []]

Example4 : Using itertools

Using the built-in repeat function from the itertools module. This function allows you to repeat a given object a certain number of times, which can be useful for creating lists of lists.

Here is an example of how you can use repeat to create a list of lists in Python:

Python3

from itertools import repeat

# Create a list of lists with 5 sub-lists
n_lists = list(repeat([], 5))

print(n_lists)  # Output: [[], [], [], [], []]

Output

[[], [], [], [], []]