Python is a popular and versatile programming language used for a variety of tasks, including data analysis, web development, and automation.

One of the most commonly used features of Python is its ability to manipulate lists, which are collections of items stored in a specific order. Two methods used to add items to a list in Python are “append()” and “extend()”.

While both methods are used to add items to a list, they have some key differences that can impact how you use them. In this article, we will explore these differences and explain when to use “append()” vs “extend()” in Python.

Introduction to Python Lists

A list is a collection of values that are enclosed within square brackets and separated by commas. Lists are mutable, which means that you can add, remove, or modify the elements of a list. Here’s an example of a Python list:

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

Understanding the Append() Method

The append() method is used to add a single element to the end of a list. It takes one argument, which is the element to be added to the list. Here’s an example:

				
					numbers = [1, 2, 3, 4, 5]
numbers.append(6)
print(numbers)  # Output: [1, 2, 3, 4, 5, 6]

Understanding the Extend() Method

The extend() method is used to add multiple elements to the end of a list. It takes one argument, which is an iterable (e.g., list, tuple, string, etc.) containing the elements to be added to the list. Here’s an example:

				
					numbers = [1, 2, 3, 4, 5]
numbers.extend([6, 7, 8])
print(numbers)  # Output: [1, 2, 3, 4, 5, 6, 7, 8]

Key Differences Between Append() and Extend()

Here are the key differences between the append() and extend() methods:

  • Argument Type: The append() method takes a single element as an argument, whereas the extend() method takes an iterable containing multiple elements.
  • Result Type: The append() method returns None, whereas the extend() method returns the modified list.
  • Modifies Original List: The append() method modifies the original list by adding a single element to the end, whereas the extend() method modifies the original list by adding multiple elements to the end.

When to Use Append()

Use the append() method when you want to add a single element to the end of a list. For example, if you have a list of numbers and you want to add a new number to the end of the list, you can use the append() method.

				
					numbers = [1, 2, 3, 4, 5]
numbers.append(6)

When to Use Extend()

Use the extend() method when you want to add multiple elements to the end of a list. For example, if you have a list of numbers and you want to add another list of numbers to the end of the list, you can use the extend() method.

				
					numbers = [1, 2, 3, 4, 5]
new_numbers = [6, 7, 8]
numbers.extend(new_numbers)

The append() and extend() methods are both useful for modifying Python lists. The key difference between them is the type of argument they take and the number of elements they add to the list. Use append() when you want to add a single element to the end of a list, and use extend() when you want to add multiple elements to the end of a list.


Thanks for reading. Happy coding!