I want to use attributes Tags and Authors to classify each record into their respective Rating. In order to do so I want to use a random forest classifier. My concern is how to deal with Tags attribute. Each of the entry has an undetermined number of tags separated by a commas. There are a total of 4412 unique tags and the entry with more tags contains 20 tags. The first entry has tags ["Rhode Island","Economy", "Taxes", "Lincoln Chafee"].
How should I encode this attribute such that I can use Random Forest Classifier from sklearn?