How to put labels over geom_bar in R with ggplot2

Question

I'd like to have some labels stacked on top of a geom_bar graph. Here's an example:

df <- data.frame(x=factor(c(TRUE,TRUE,TRUE,TRUE,TRUE,FALSE,FALSE,FALSE))) ggplot(df) + geom_bar(aes(x,fill=x)) + opts(axis.text.x=theme_blank(),axis.ticks=theme_blank(),axis.title.x=theme_blank(),legend.title=theme_blank(),axis.title.y=theme_blank()) 

Now

table(df$x)

FALSE  TRUE      3     5  

I'd like to have the 3 and 5 on top of the two bars. Even better if I could have the percent values as well. E.g. 3 (37.5%) and 5 (62.5%). Like so:
_{(source: skitch.com)}

Is this possible? If so, how?

Answer 1

To plot text on a ggplot you use the geom_text. But I find it helpful to summarise the data first using ddply

dfl <- ddply(df, .(x), summarize, y=length(x)) str(dfl) 

Since the data is pre-summarized, you need to remember to change add the stat="identity" parameter to geom_bar:

ggplot(dfl, aes(x, y=y, fill=x)) + geom_bar(stat="identity") +     geom_text(aes(label=y), vjust=0) +     opts(axis.text.x=theme_blank(),         axis.ticks=theme_blank(),         axis.title.x=theme_blank(),         legend.title=theme_blank(),         axis.title.y=theme_blank() )