How to put labels over geom_bar in R with ggplot2

user_382745 0
Viewed 174684

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?

ggplot2 r
4 Answers

Another solution is to use stat_count() when dealing with discrete variables (and stat_bin() with continuous ones).

ggplot(data = df, aes(x = x)) +
geom_bar(stat = "count") + 
stat_count(geom = "text", colour = "white", size = 3.5,
aes(label = ..count..),position=position_stack(vjust=0.5))

enter image description here

user_78088790

So, this is our initial plot↓

library(ggplot2)

df <- data.frame(x=factor(c(TRUE,TRUE,TRUE,TRUE,TRUE,FALSE,FALSE,FALSE)))

p <- ggplot(df, aes(x = x, fill = x)) +
  geom_bar()
p

initial barplot without labels

As suggested by yuan-ning, we can use stat_count().

geom_bar() uses stat_count() by default. As mentioned in the ggplot2 reference, stat_count() returns two values: count for number of points in bin and prop for groupwise proportion. Since our groups match the x values, both props are 1 and aren’t useful. But we can use count (referred to as “..count..”) that actually denotes bar heights, in our geom_text(). Note that we must include “stat = 'count'” into our geom_text() call as well.

Since we want both counts and percentages in our labels, we’ll need some calculations and string pasting in our “label” aesthetic instead of just “..count..”. I prefer to add a line of code to create a wrapper percent formatting function from the “scales” package (ships along with “ggplot2”).

pct_format = scales::percent_format(accuracy = .1)

p <- p + geom_text(
    aes(
      label = sprintf(
        '%d (%s)',
        ..count..,
        pct_format(..count.. / sum(..count..))
      )
    ),
    stat = 'count',
    nudge_y = .2,
    colour = 'royalblue',
    size = 5
  )
p

barplot with labels

Of course, you can further edit the labels with colour, size, nudges, adjustments etc.

user_34435000
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