The notebook (right-click and download this file)
takes you through the initial steps of fitting a Decision Tree Classifier to
the Play Tennis data set, which should be
downloaded and and should be placed in a data subfolder of the folder where you
placed the notebook.
The notes explain how the algorithm works. Running the code cells shows the expressions to be evaluated, and their values. As such, you might find this worked example helps you to understand the way that decision trees learn, supplementing the explanations in the lecture notes.
There is also an exercise for the student, developing the Decision Tree model that was presented in the notebook.