[R] groupedData function not found

[andrea previtali]

Hello,
I'm trying to use the groupedData function and R is giving me the message: Error: can not find function "groupedData"
The code is coming from a textbook so I think it should be correct:

pigs<-data.frame(cbind(pig.time,pig.id,pig.wt))
pig.growth<-groupedData(pig.wt~pig.time|pig.id,data=pigs)

I have added the package "nlme" and to confirm that it was installed correctly I requested the list of functions included in the package (library(help=nlme)) and I do see groupData in the list.
I am using R 2.6.1 in Windows XP.

I'll appreciate your help.
Thanks,
Andrea Previtali
Post-doc fellow
Dept. of Biology,
Univ. of Utah, SLC, UT.