# How to input dataset with multi-value properties?

I'm trying to learn to use AI, and so I've followed some basic tutorials like training an MLP to predict the price of a car given properties like its age and manufacturer. Now I want to see if I can do it myself, so I thought it'd be fun to predict what score I would give a movie given some data scraped off IMDB.

I immediately got stuck, because how do you deal with the cast? A single property with multiple values, where a particular actor may impact the final score (or a combination of actors - that's for the neurons to suss out).

I haven't found a way to do this when googling, but it may just be that I'm unfamiliar with the terminology. Or have I accidentally chosen a really difficult problem?

Note that I'm completely new to all of this, so if you have suggestions, please try to put it as simply as possible.

The caveat is that to represent all actors, you'd need a rediculously long vector. In such cases, it's often sufficient to only look at the most common, say, 100 and ignore the rest. It intuitively makes sense that having a big actor who's done a lot of movies says more about the quality of a movie than whoever's playing Unimportant Bystander #3. This is actually how natural language processing represents words in the English language - take the top n and ignore the rest.