Did you do your homework? I hope so. Hopefully, you were able to draw on our previous examples and now have a running script that adds up the total amount spent by customer in my little fake dataset. Let's compare your implementation to my implementation and your results to mine and see if they match up. If they don't, hopefully you'll learn something from it.

Let's have a look at my solution. If you go to the download package for this book, you will see my total-spent-by-customer script, feel free to download that and put it into your SparkCourse folder alongside your own solution to this problem and the book.txt file that you should have from the previous section. Go ahead and open that up. When you're ready, here's my take at it:

This is a very simple script, but the idea was just to get you into the practice of writing your own Spark programs. Even if it's a simple one, writing your first program is a big accomplishment. Let's...