grouped bar plots

# ggplot für mehrere bargraphen hintereinander
library(ggplot2)
library(plyr)
library(reshape2)

melted <- melt(statistik_master_satz, id.vars=c("Droge"))

means <- ddply(melted, c("Droge", "variable"), summarise,
               mean=mean(value)
)

means$Droge <- factor(
  means$Droge,
  levels=rev(sort(unique(means$Droge))),
  ordered=TRUE
)

means2 <- means
names(means2)[names(means2)=="mean"]  <- "Anzahl"
names(means2)[names(means2)=="variable"]  <- "Legende"

ggplot(means2, aes(x=Droge, y=Anzahl, fill=Legende, horiz=TRUE)) +
  geom_bar(stat="identity", position="dodge") +
  coord_flip()