Display minimum value on top of column graph in R

Question

I'm trying to display the minimum value for the category on top of each column bar. But it ends up displaying multiple values instead of the minimum.

ggplot(subset(new_data, device %in% "Thera_PEP"),
       aes(setting, pressure, group = setting, fill = setting)) +
  geom_col(position = "dodge",
           stat = "summary",
           fun = "min") + scale_x_continuous(breaks = seq(1, 6, 1)) + 
  scale_y_continuous(label = scales::comma) + theme_classic() + 
  ylab("Minimum Trigger Pressure") + 
  xlab("Device setting") + 
  geom_text(aes(label = min(pressure)), position=position_dodge(width=0.9), vjust=-0.25)

Welcome to SO, user21046947! Questions on SO (especially in R) do much better if they are reproducible and self-contained. By that I mean including attempted code (please be explicit about non-base packages), sample representative data (perhaps via `dput(head(x))` or building data programmatically (e.g., `data.frame(...)`), possibly stochastically), perhaps actual output (with verbatim errors/warnings) versus intended output. Refs: https://stackoverflow.com/q/5963269, [mcve], and https://stackoverflow.com/tags/r/info. — r2evans, Jan 22 '23 at 22:48

score 3 · Answer 1 · answered Jan 22 '23 at 22:50

To display only the minimum value per setting you have to use stat="summary" with fun="min" if geom_text. Also, note that geom_col has no stat argument. Hence, I would suggest to switch to geom_bar.

Using some fake data based on mtcars:

new_data <- mtcars[c("cyl", "mpg")]
names(new_data) <- c("setting", "pressure")
new_data$device <- "Thera_PEP"

library(ggplot2)

ggplot(
  subset(new_data, device %in% "Thera_PEP"),
  aes(setting, pressure, group = setting, fill = setting)
) +
  geom_bar(
    position = "dodge",
    stat = "summary",
    fun = "min"
  ) +
  scale_x_continuous(breaks = seq(1, 6, 1)) +
  scale_y_continuous(label = scales::comma) +
  theme_classic() +
  ylab("Minimum Trigger Pressure") +
  xlab("Device setting") +
  geom_text(aes(label = after_stat(y)),
    stat = "summary",
    fun = "min",
    position = position_dodge(width = 0.9), vjust = -.25
  )

Display minimum value on top of column graph in R

1 Answers1