barplot_values_ggplot2

barplot_values_ggplot2.R

library(ggplot2)
library(plyr)
data(mpg)

# create a data frame with averages and standard deviations
hwy.means <- ddply(mpg, c("class", "year"), summarize,  hwy.avg = mean(hwy), hwy.sd = sd(hwy))

# barplot with values over bars
ggplot(hwy.means) + 
    geom_bar(aes(class, hwy.avg, fill = factor(year)), position = "dodge", colour = "black", size = 0.3) +
    geom_text(aes(class, hwy.avg, label = sprintf("%2.1f", hwy.avg)), 
        position = position_dodge(width = 1), size = 3.5, vjust = -0.3, colour = "grey10") + 
    scale_fill_hue(c=90, l=55) +
    theme_bw()