Python for Machine Learning - The Complete Beginners Course - Data Pre-Processing

The video tutorial explains how to create a matrix with user IDs and movie titles to display user ratings. It uses the pivot_table function to structure the data, with user IDs as the index, movie titles as columns, and ratings as values. The tutorial highlights the presence of null values due to users not rating all movies and emphasizes the need for data preprocessing. Finally, it suggests sorting the most rated movies for better analysis.

Why are there null values in the movie rating data?

What steps should be taken to preprocess the movie rating data?