Category: R

In ggplot2 it is not so easy to change the scale position, like showing the Y-axis in the right side or using dual axis. Kohske Takahashi is working on it and it is available in the dev version. (https://groups.google.com/forum/?fromgroups=#!topic/ggplot2-dev/JkJU5CLBkQw). As alternative he provided a solution with gtable http://rpubs.com/kohske/dual_axis_in_ggplot2. For simply change the Y-axis to the right side see http://stackoverflow.com/questions/15334494/how-to-change-positions-of-x-and-y-axis-in-ggplot2

Dual axis:
library(ggplot2)
library(gtable)
library(grid)
grid.newpage()
# two plots
p1 <- ggplot(mtcars, aes(mpg, disp)) + geom_line(colour = "blue") + theme_bw()
p2 <- ggplot(mtcars, aes(mpg, drat)) + geom_line(colour = "red") + theme_bw() %+replace%
theme(panel.background = element_rect(fill = NA))
# extract gtable
g1 <- ggplot_gtable(ggplot_build(p1))
g2 <- ggplot_gtable(ggplot_build(p2))
# overlap the panel of 2nd plot on that of 1st plot
pp <- c(subset(g1$layout, name == "panel", se = t:r))
g <- gtable_add_grob(g1, g2$grobs[[which(g2$layout$name == "panel")]], pp$t,
pp$l, pp$b, pp$l)
# axis tweaks
ia <- which(g2$layout$name == "axis-l")
ga <- g2$grobs[[ia]]
ax <- ga$children[[2]]
ax$widths <- rev(ax$widths)
ax$grobs <- rev(ax$grobs)
ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm")
g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1)
g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)
# draw it
grid.draw(g)
Y axis in right:
library(ggplot2)
library(gtable)
library(grid)
grid.newpage()
dat <- data.frame(x<-seq(0, 10, 0.1),y = sin(x * pi))
p <- ggplot(dat, aes(x, y)) + geom_line(colour = "blue") + theme_bw()
# extract gtable
g <- ggplot_gtable(ggplot_build(p))
# axis tweaks
ia <- which(g$layout$name == "axis-l")
ax <- g$grobs[[ia]]$children[[2]]
ax$widths <- rev(ax$widths)
ax$grobs <- rev(ax$grobs)
ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm")
pp <- c(subset(g$layout, name == "panel", select = t:r))
g <- gtable_add_cols(g, g$widths[g$layout[ia, ]$l], length(g$widths) - 1)
g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)
g$grobs[[ia]]$children[[2]] <- NULL
##############################
ia <- which(g$layout$name == "ylab")
ylab <- g$grobs[[ia]]
g <- gtable_add_cols(g, g$widths[g$layout[ia, ]$l], length(g$widths) - 1)
g <- gtable_add_grob(g, ylab, pp$t, length(g$widths) - 1, pp$b)
g$grobs[[ia]]$label = ''
grid.draw(g)