lattice separate y axes for row of xyplot

Question

I wish to have the same y-axis limits for a row of an xyplot with a 2 by 2 display. Neither scales = "free", nor scales = "sliced" will achieve this.

toy example

size <- rep(c("da","db","ca","cb"),each=5)  
age <- rep(1:5,4)  
growth <- rep(c(-75,-55,-25,-20),each=5)  

test <- data.frame(size,age,growth)


xyplot(growth~age|factor(size),layout=c(2,2),
 type=c("p","g"),
 scales=list(x=list(tick.number=3)),
 ylab="growth %",xlab="age",pch=20,col="black",
 data=test)

in this case I would like to have (in base graphics): ylim=c(-50,-80) for the first row and y=c(-20,-30) for the second row.

Answer 1

You need to pass a list of limits to the xyplot. Here I made a list outside of the xyplot function but you could do that right in the scales argument if you wish.

library(lattice)
size <- rep(c("da","db","ca","cb"),each=5) 
age <- rep(1:5,4)
growth <- rep(c(-75,-55,-25,-20),each=5)
test <- data.frame(size,age,growth)

YLims<-list(c(-20,30),c(-20,30),c(-50,-80),c(-50,-80) )

xyplot(growth~age|factor(size),
   layout=c(2,2), 
   type=c("p","g"), 
   scales=list(x=list(tick.number=3), y=list(relation="free", limits=YLims)), 
   ylab="growth %",xlab="age",pch=20,col="black",  data=test)