[R] Alternate tick labels in xyplot

[Lisa Daniel]

Dear Rhelp,
I was able to solve the tick labels part.  If somebody can help me in creating title for each row of figures above the individual headings, it will be great.
library(grid)
library(lattice)
xy <-xyplot(decrease ~ treatment, OrchardSprays,
    main= "Some plot",
        groups = rowpos, type = "a",
    scales=list(x=list(at=seq(1,8,1),labels=c('A','','C','','E','','G',''))),
                page     = function(n){
                         grid.text(LETTERS[j],
                         y = 0.95,
                         x = 0.15,
                         default.units = "npc",
                         just = c("left"),
                         gp = gpar(fontsize = 12,fontface="bold") )
                       },
    par.settings = c(simpleTheme(lty=1:8, col="black",lwd=2),list(axis.components=list(bottom=list(tck=c(0,1))),layout.heights = list(main = 1.2,
                       sub  = 0,
                       axis.top = 0.2,
                       top.padding  = 0.1,
                       bottom.padding = 0)) ),
        auto.key = list(x = 0.2, y = 0.9,
        cex = 0.75, points = FALSE, lines = TRUE)) 
j=1
print(xy, pos = c(0.0, 0.5, 0.33, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.33, 0.5, 0.66, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.66, 0.5, 0.99, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.0, 0.0, 0.33, 0.5), more = TRUE)
j=j+1
print(xy, pos = c(0.33, 0.0, 0.66, 0.5), more = TRUE)
j=j+1
print(xy, pos = c(0.66, 0.0, 0.99, 0.5), more = FALSE)

Many thanks,
Lisa




----- Original Message -----
From: Lisa Daniel <lisadaniel2013 at yahoo.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc: 
Sent: Thursday, February 14, 2013 12:14 PM
Subject: Alternate tick labels in xyplot

Dear Rhelp,

I would like to get alternate tick labels for the xyplot:
library(lattice)
library(grid)

xy <-xyplot(decrease ~ treatment, OrchardSprays,
    main= "Some plot",
        groups = rowpos, type = "a",
                page     = function(n){
                         grid.text(LETTERS[j],
                         y = 0.95,
                         x = 0.15,
                         default.units = "npc",
                         just = c("left"),
                         gp = gpar(fontsize = 12,fontface="bold") )
                       },
    par.settings = c(simpleTheme(lty=1:8, col="black",lwd=2),list(layout.heights = list(main = 1.2,
                       sub  = 0,
                       axis.top = 0.2,
                       top.padding  = 0.1,
                       bottom.padding = 0)) ),
        auto.key = list(x = 0.2, y = 0.9,
        cex = 0.75, points = FALSE, lines = TRUE)) 
j=1
print(xy, pos = c(0.0, 0.5, 0.33, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.33, 0.5, 0.66, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.66, 0.5, 0.99, 1.0), more = TRUE)
j=j+1
print(xy, pos = c(0.0, 0.0, 0.33, 0.5), more = TRUE)
j=j+1
print(xy, pos = c(0.33, 0.0, 0.66, 0.5), more = TRUE)
j=j+1
print(xy, pos = c(0.66, 0.0, 0.99, 0.5), more = FALSE)


similar to the x-axis in the code below, but somehow it is not working when I pasted 'list(axis.components=...) in the above code:
xyplot(rnorm(12) ~ 1:12 , type="l",
scales=list(x=list(at=seq(2,12,2),labels=c(1, ' ', 3 , ' ' , 5 , ' ' ))),
par.settings=list(axis.components=list(bottom=list(tck=c(0,1))))) 

scales=list(x=list(at=seq(1,8,1),labels=c('A', ' ', 'C', ' ' ,'E' , ' ','G',' '))),

If possible, I would like a heading for each rows (justified to center) above the individual heading.

Please help.
Many thanks,
Lisa.