[R] How do I perform conditional annotation of lattice panel plots?

[Ken Knoblauch]

Chen, George <George.Chen <at> roswellpark.org> writes:
> My apologies for asking this question that may have 
been asked before. I am trying to plot activity
> dependent on time conditioned by the subject. 
Code for sample data below.
> So I have something like this
> xyplot(Activity~Time|Subject).
> This works fine, but now I want to show 
where on these activity curves Event A occurs. 
This is to explore the
> relationship between A and activity.
> 
> I tried this:
> 
> xyplot(EventA+Activity~Time|Subject)
> 
> but then the numerical ordering gets out of order.
> Ideally Event A could be denoted by a vertical line 
cutting through the curve at the day Event A occurred, but
> some other way to denote it would be great!
> 
-----snip -------------
> Any ideas on how to do this would be appreciated!
> 
> Thanks very much in advance!
> 
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You used Time in your formula but Day in 
your data so I changed the formula to Day
assuming that's what you meant

Perhaps, not the most elegant solution, but 
how about something like this

library(lattice)
Subject<-c(1,1,1,1,1,1,2,2,2,2,2,2,3,3,3,3,3,3,4,4,4,4,4,4)
Day<-c(1,2,3,4,5,6,1,2,3,4,5,6,1,2,3,4,5,6,1,2,3,4,5,6)
Activity<-c(2,3,4,3,7,4,5,8,2,8,4,6,2,5,3,8,9,5,6,3,4,5,6,7)
EventA<-c("Yes",NA,"Yes",NA,NA,NA,"Yes",NA,NA,NA,NA,NA,
          "Yes",NA,NA,NA,NA,NA,NA,NA,"Yes",NA,NA,NA)
Data<-data.frame(cbind(Subject,Day,Activity,EventA))

xyplot(Activity~ Day | Subject)
xyplot(Activity ~ Day | Subject, data = Data,
	subscripts = TRUE,
	panel = function(x, y, subscripts, ...){
		panel.xyplot(x, y)
		wh <- Data[subscripts, ]
		panel.abline(v = wh$Day[!is.na(wh$EventA)])
	})


-- 
Kenneth Knoblauch
Inserm U846
Stem-cell and Brain Research Institute
Department of Integrative Neurosciences
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