I want to add multiples lines using geom_errorbar in a single bar with geom_bar with ggplot2 in R

I used an example similar to:

so if I use the next data frame with multiples lines in upper column

df2 <- data.frame(
    resp = rep(c(50, 50, 50, 50),4),
    group = factor( rep(c("G1", "G2", "G3", "G4"), 4)), 
    upper = c(10, 17, 49, 40, 40, 33, 42, 47, 29, 25, 33, 41, 49, 22, 32, 33)
)

then plot it

ggplot(df2, aes(x=group, y=resp, fill = group))   
    geom_bar(stat = "identity")  
    geom_errorbar(aes(ymin = upper, ymax = upper), size = 0.5, linetype=1, alpha=1, color="white")

it will add multiples lines, but the bars in Y axis up to 200!!

How can I fix it, just to get to 50 in Y axis instead to 200?

do I have to use 2 data frames ?

Thanks !!!

CodePudding user response：

The issue with your second trial is that you have multiple resp values per group which by default get stacked and each bars sums to 200 = 4 x 50. Instead I would suggest to use two separate data frames, one for the bars, one for the lines:

library(ggplot2)

df_bars <- data.frame(
  resp = c(50, 50, 50, 50),
  group = factor(c("G1", "G2", "G3", "G4"))
)

df_lines <- data.frame(
  group = factor(rep(c("G1", "G2", "G3", "G4"), 4)),
  upper = c(10, 17, 49, 40, 40, 33, 42, 47, 29, 25, 33, 41, 49, 22, 32, 33)
)

ggplot(mapping = aes(x = group))  
  geom_col(aes(y = resp, fill = group), data = df_bars)  
  geom_errorbar(aes(ymin = upper, ymax = upper), data = df_lines, 
                size = 0.5, linetype = 1, alpha = 1, color = "white")