Message-ID: <20060822095330.BGL29643@po-d.temple.edu>
Date: 2006-08-22T13:53:30Z
From: Richard M. Heiberger
Subject: aggregate example : where is the state.region variable?
> 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.