[R] How to interpret some diagnostic output

[Gerald I. Evenden]

I do not know if I have a problem or not.

The R script at the end of this email seems to
run properly and a I get a boxplot that looks
proper but I get the long string of messages
during execution of the script looking like:

...
       The following object(s) are masked from dat ( position 8 ) :

         sugar


        The following object(s) are masked from dat ( position 9 ) :

         sugar


        The following object(s) are masked from dat ( position 10 ) :

         sugar

...
I have absolutely no idea what they mean.

An interprestion or suggestion would be greatly
appreciated.

Running on Kubuntu using
R version 2.6.2 (2008-02-08)

PS: I'm obviously a newbie and this script is my first serious
attempt at using R.

R text follows: --------------------

source("dbi-start.R")
am_pm<-"PM Glucose for"
fc_year<-2008
bfc_head<-"select blood.sugar from blood where"
bfc_PM<-"blood.time>\"22:00:00\" and blood.time<=\"23:59:00\""
bfc_tail<-"order by blood.date,blood.time"
bfc<-"blood.date"
nmon<-c(2:12,1)

lst<-list() # init null list
for (i in 1:12) {
	year<-fc_year
	fc_date <- paste(bfc,">=\"", year, "-", i, "-01\" and ", sep="")
	if (i == 12) year<-fc_year+1 else year<-fc_year
	fc_date <-	paste(fc_date,bfc,"<\"",year,"-",nmon[i],"-01\" and ",sep="")
	fc_res<-dbSendQuery(gielog, paste(bfc_head,fc_date,bfc_PM,bfc_tail))
	dat<-fetch(fc_res, n=-1)
	attach(dat)
	lst<-c(lst,list(sugar))
}
boxplot(lst,
	main=paste(am_pm, fc_year),
	mai=c(.5,.5,.5,.3),
	axis=FALSE,
	ylab="Glucose", xlab="Month")
axis(2,seq(40,200,by=10))
axis(4,seq(40,200,by=10))
axis(1,1:12)


-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist