How To add Elements to a List in Python

Introduction

In this tutorial, we will learn different ways to add elements to a list in Python.

There are four methods to add elements to a List in Python.

1. append(): append the element to the end of the list.
2. insert(): inserts the element before the given index.
3. extend(): extends the list by appending elements from the iterable.
4. List Concatenation: We can use the + operator to concatenate multiple lists and create a new list.

Prerequisites

In order to complete this tutorial, you will need:

• Familiarity with installing Python 3. And familiarity with coding in Python. How to Code in Python 3 series or using VS Code for Python.

This tutorial was tested with Python 3.9.6.

append()

This function adds a single element to the end of the list.

fruit_list = ["Apple", "Banana"]

print(f'Current Fruits List {fruit_list}')

new_fruit = input("Please enter a fruit name:\n")

fruit_list.append(new_fruit)

print(f'Updated Fruits List {fruit_list}')

Output:

Current Fruits List ['Apple', 'Banana']
Please enter a fruit name:
Orange
Updated Fruits List ['Apple', 'Banana', 'Orange']

This example added Orange to the end of the list.

insert()

This function adds an element at the given index of the list.

num_list = [1, 2, 3, 4, 5]

print(f'Current Numbers List {num_list}')

num = int(input("Please enter a number to add to list:\n"))

index = int(input(f'Please enter the index between 0 and {len(num_list) - 1} to add the number:\n'))

num_list.insert(index, num)

print(f'Updated Numbers List {num_list}')

Output:

Current Numbers List [1, 2, 3, 4, 5]
Please enter a number to add to list:
20
Please enter the index between 0 and 4 to add the number:
2
Updated Numbers List [1, 2, 20, 3, 4, 5]

This example added 20 at the index of 2. 20 has been inserted into the list at this index.

extend()

This function adds iterable elements to the list.

extend_list = []

extend_list.extend([1, 2])  # extending list elements

print(extend_list)

extend_list.extend((3, 4))  # extending tuple elements

print(extend_list)

extend_list.extend("ABC")  # extending string elements

print(extend_list)

Output:

[1, 2]
[1, 2, 3, 4]
[1, 2, 3, 4, 'A', 'B', 'C']

This example added a list of [1, 2]. Then it added a tuple of (3, 4). And then it added a string of ABC.

List Concatenation

If you have to concatenate multiple lists, you can use the + operator. This will create a new list, and the original lists will remain unchanged.

evens = [2, 4, 6]
odds = [1, 3, 5]

nums = odds + evens

print(nums)  # [1, 3, 5, 2, 4, 6]

This example added the list of evens to the end of the list of odds. The new list will contain elements from the list from left to right. It’s similar to the string concatenation in Python.

Conclusion

Python provides multiple ways to add elements to a list. We can append an element at the end of the list, and insert an element at the given index. We can also add a list to another list. If you want to concatenate multiple lists, then use the overloaded + operator

References:

• Python List
• Python.org Docs