[R] lme4 groupedData is missing

Deepayan Sarkar deepayan at stat.wisc.edu
Sat Jul 24 01:22:20 CEST 2004

On Friday 23 July 2004 16:28, Jacob Wegelin wrote:

> help.search("groupedData") says that it's part of the lme4 package,
> but it appears not to be there (details below). Is this because lme4
> is new and (perhaps) still under development?

Yes, sort of. The groupedData class in nlme inherits from "data.frame". 
Since "data.frame" is not an S4 class, this is difficult to emulate, 
and we are still experimenting on how to represent grouping 
information. The groupedData class in lme4 is one attempt, but the 
current plans are to scrap it and just have the grouping information as 
attributes on a data frame.

It so happens that the current groupedData function is not exported, 
which is why you can't see it. That's an oversight on my part, but 
since it will probably go away anyway, this is a good thing.


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