> there is > no factor in the dataset but why there is not one and > why a call to another dataset is totally opaque.
The reason is purely historical. The state dataset is about 10 years older than the data.frame concept. At the time the state.* variables were constructed it was not possible to put numeric data and factor data into the same rectangular structure. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
