How to create a list of lists in Python?
Tags: python, programming, tutorial, beginners
Published: 2022-03-25 06:56:50

Do not get afraid of the name- list of lists. It is nothing but a list with other lists as an element. In this tutorial, we will learn about the different ways to create List of lists in Python.  

### Table of contents

*   [What is a list of lists?](#what-is-a-list-of-lists)
*   [Using append() function to create a list of lists in Python](#using-append-function-to-create-a-list-of-lists-in-python)
*   [Create a list of lists using the list initializer in Python](#create-a-list-of-lists-using-the-list-initializer-in-python)
*   [Using list comprehension to create a list of lists](#using-list-comprehension-to-create-a-list-of-lists)
*   [Using for-loop to create a list of lists in Python](#using-forloop-to-create-a-list-of-lists-in-python)
*   [Closing thoughts](#closing-thoughts)

<span id="section1"></span>  

## What is a list of lists?

In any programming language, lists are used to store more than one item in a single variable. In Python, we can create a list by surrounding all the elements with square brackets [] and each element separated by commas. It can be used to store integer, float, string and more.  

Python provides an option of creating a list within a list. If put simply, it is a nested list but with one or more lists inside as an element.  

Here is an example of a list of lists to make things more clear:  

    [[a,b],[c,d],[e,f]]

Here, [a,b], [c,d], and [e,f] are separate lists which are passed as elements to make a new list. This is a list of lists.  

<span id="section2"></span>Now we will discuss different ways to create a list of lists in Python.  

## Using append() function to create a list of lists in Python

What append() function does is that it combines all the lists as elements into one list. It adds a list at the end of the list.  
In order to have a complete understanding of how this functions works, we will create two lists and then using the append() function we will combine them into one list  

#### Input:

    # Create 2 independent lists
    list_1 = [a,b,c]
    list_2 = [d,e,f]

    # Create an empty list
    list = []

    # Create List of lists
    list.append(list_1)
    list.append(list_2)
    print (list)

#### Output:

    [[a,b,c],[d,e,f]]

## Create a list of lists using the list initializer in Python

Using a list initializer, we treat lists as elements. We create a list of lists by passing lists as elements. It is the easiest way to create a list of lists.  

#### Input:

    # Create 2 independent lists 
    list_1 = [a,b,c] 
    list_2 = [d,e,f]

    # Create List of lists 
    list = [list1, list2]

    # Display result
    print(list)

#### Output:

    [[a,b,c],[d,e,f]]

<span id="section4"></span>

## Using list comprehension to create a list of lists

List comprehension is a bit complicated yet short method to create a list of lists in Python.  

#### Input:

    list_1 = [a,b,c]
    list = [l1 for i in range(3)]
    print(list)

#### Output:

    [[a,b,c],[a,b,c],[a,b,c]]

<span id="section5"></span>

## Using for-loop to create a list of lists in Python

You can use the for-loop to create a list of lists to create too. Here is a code snippet for better understanding.  

#### Input:

    list = []

    # Create List of list
    for i in range(2):
        list.append([])
        for j in range(3): 
            list[i].append(j)

    print(lst) 

#### Output:

    [[a,b,c],[a,b,c]]

<span id="section6"></span>

## Closing thoughts

A list of lists is a list where each element is a list by itself. The [List](https://www.w3schools.com/python/python_lists.asp) is one of the 4 built-in data types in Python. One can learn more about other Python data types [here](https://flexiple.com/check-if-list-is-empty-python).