Real Python - Counting With Python's Counter By Christopher Trudeau

This dictionary subclass provides efficient counting capabilities out of the box. Understanding Counter and how to use it efficiently is a convenient skill to have as a Python developer.
In this video course, you'll learn how to
Count several repeated objects at once
Create counters with Python's Counter
Retrieve the most common objects in a counter
Update object counts
Use Counter to facilitate further computations
Implement Counter instances as multisets
Homepage

https://realpython.com/courses/counting-python-counter/