Fixing a new problem in some DBDA2E scripts caused by a change in R 4.0.0

UPDATE: Scripts are now changed to work with R 4.1; see this blog post. 

The scripts that accompany DBDA2E have worked fine, "out of the box," for years. But recently some scripts have had problems. Why? R has changed. With R 4.0.0, various functions such as read.csv() no longer automatically convert strings to factors. Some DBDA2E scripts assumed the results of those functions contained factors, but if you're now using R 4.0.0 (or more recent) those scripts will balk. 

So, what to do? Here's a temporary fix. When you open your R session, type in this global option:

options(stringsAsFactors = TRUE)

Unfortunately this option will eventually be deprecated. I'll have to modify every affected script and post updated versions. This will happen someday. I hope.

Why did R change? You can read about it here: 

https://developer.r-project.org/Blog/public/2020/02/16/stringsasfactors/index.html