Real Python – Python’s len() Function

In many situations, you’ll need to find the number of items stored in a data structure. Python’s built-in function len() is the tool that will help you with this task.

There are some cases in which the use of len() is straightforward. However, there are other times when you’ll need to understand how this function works in more detail and how to apply it to different data types.

In this course, you’ll learn how to

Find the length of built-in data types using len()

Use len() with third-party data types

Provide support for len() with user-defined classes