How to show important values on a graph with ggplot?

Question

How do I show the specific values of variables on a graph? For example: ggplot(data=df)+ geom_bar(mapping=aes(x=var))

How do I get it to have the actual count on the bar chart?

Answer 1

I believe this question has asked before but I couldn' find a duplicate quickly.

Here is an example how to annotate the columns of a bar chart with the counts:

n_row <- 100L
set.seed(123L)
df <- data.frame(var = sample(LETTERS[1:5], n_row, TRUE, 5:1))

library(ggplot2)
ggplot(data = df) + aes(x = var) + 
  geom_bar() + 
  stat_count(geom = "text", aes(label = ..count..), vjust = "bottom")

Alternatively, we can write

ggplot(data = df) + aes(x = var, label = ..count..) + 
  geom_bar() + 
  geom_text(stat = "count", vjust = "bottom")

Some geoms and stats do compute variables which can be accessed using special names like ..count... To plot labels, the x and y positions and the text need to be specified. The x position is taken from the date as specified in aes(). The y position seems to be taken automatically from the statistical transformation but the text needs to be specified explicitely.

Suggested reading:

• Statistical transformations in R for Data Science
• ggplot2 homepage