ggplotly - only show the top whisker of an errorbar

Question

I have a ggplot barplot with an errorbar, which I'm putting through ggplotly. My preference is to only show the top of the errorbar. In ggplot2, I simply specify the y_min of the errorbar to be the value of the bar, and plot the errorbar first, so that the bottom whisker is hidden behind the geom_bar. However, once I run the plot through ggplotly, the errorbar is shown on the top. Is there a way to not show the bottom whisker? I searched for ways to change the order of the 2 traces, or options for "top-only" errorbars, but couldn't find anything.

library(dplyr)
library(ggplot2)
library(plotly)

df <- data.frame(y = c(5, 10), group = c("a", "b"))
p <- ggplot(df) +
        geom_errorbar(aes(x = group, ymin = y, ymax = y + 10), linewidth = 0.1, width = 0.7) +
        geom_bar(aes(x = group, y = y), stat = "identity", fill = "lightgrey") 

# only top whisker is shown     
p 

# both top and bottom are showing
ggplotly(p) 

Answer 1

Presumably there is a way to hack the plotly object to move the error bar so that it is underneath the bars, though a simpler solution might be to draw only the objects you want visible. You can do this by drawing a zero-height errorbar at ymax and a segment between y and ymax. That way the layer order doesn't matter.

p <- ggplot(df, aes(x = group, ymax = y + 10)) +
  geom_errorbar(aes(ymin = y + 10, ymax = y + 10), 
                linewidth = 0.1, width = 0.7) +
  geom_linerange(aes(ymin = y), linewidth = 0.5) +
  geom_col(aes(x = group, y = y), fill = "lightgrey") 

ggplotly(p) 

It's important to point out that the vertical line segments in either case add no information to your plot, and one could argue that having just the zero-height errorbar as a horizontal line floating above the bar might be preferable to data visualization purists.

As a footnote, geom_col() superseded geom_bar(stat = "identity") about 8 years ago.