Adding a single label per group in ggplot with stat_summary and text geoms

Question

I would like to add counts to a ggplot that uses stat_summary().

I am having an issue with the requirement that the text vector be the same length as the data.

With the examples below, you can see that what is being plotted is the same label multiple times.

The workaround to set the location on the y axis has the effect that multiple labels are stacked up. The visual effect is a bit strange (particularly when you have thousands of observations) and not sufficiently professional for my purposes. You will have to trust me on this one - the attached picture doesn't fully convey the weirdness of it.

I was wondering if someone else has worked out another way. It is for a plot in shiny that has dynamic input, so text cannot be overlaid in a hardcoded fashion.

I'm pretty sure ggplot wasn't designed for the kind of behaviour with stat_summary that I am looking for, and I may have to abandon stat_summary and create a new summary dataframe, but thought I would first check if someone else has some wizardry to offer up.

This is the plot without setting the y location:

library(dplyr)
library(ggplot2)


df_x <- data.frame("Group" = c(rep("A",1000), rep("B",2) ),
                   "Value" = rnorm(1002))
df_x <-  df_x %>%  
  group_by(Group) %>%
  mutate(w_count = n())
      

ggplot(df_x, aes(x = Group, y = Value)) +

    stat_summary(fun.data="mean_cl_boot", size = 1.2) +
    geom_text(aes(label = w_count)) +
    coord_flip() +
    theme_classic()

and this is with my hack


ggplot(df_x, aes(x = Group, y = Value)) +

    stat_summary(fun.data="mean_cl_boot", size = 1.2) +
    geom_text(aes(y = 1, label = w_count)) +
    coord_flip() +
    theme_classic()

andrew_reece · Accepted Answer · 2020-10-02 05:10:19Z

2

Create a df_text that has the grouped info for your labels. Then use annotate:

library(dplyr)
library(ggplot2)

set.seed(123)

df_x <- data.frame("Group" = c(rep("A",1000), rep("B",2) ),
                   "Value" = rnorm(1002))

df_text <- df_x %>% 
  group_by(Group) %>% 
  summarise(avg = mean(Value),
            n = n()) %>%
  ungroup()

yoff <- 0.0
xoff <- -0.1

ggplot(df_x, aes(x = Group, y = Value)) +
  stat_summary(fun.data="mean_cl_boot", size = 1.2) +
  annotate("text", 
           x = 1:2 + xoff, 
           y = df_text$avg + yoff,
           label = df_text$n) +
  coord_flip() +
  theme_classic()

answered Oct 2, 2020 at 5:10

andrew_reece

21.4k3 gold badges40 silver badges64 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

racho · Accepted Answer · 2020-10-05 00:21:00Z

1

I found another way which is a little more robust for when the plot is dynamic in its ordering and filtering, and works well for faceting. More robust, because it uses stat_summary for the text.

library(dplyr)
library(ggplot2)


df_x <- data.frame("Group" = c(rep("A",1000), rep("B",2) ),
                   "Value" = rnorm(1002))

counts_df <- function(y) {
  return( data.frame( y = 1, label = paste0('n=', length(y)) ) )
}


ggplot(df_x, aes(x = Group, y = Value)) +

    stat_summary(fun.data="mean_cl_boot", size = 1.2) +
    coord_flip() +
    theme_classic()

p + stat_summary(geom="text", fun.data=counts_df)

answered Oct 5, 2020 at 0:21

racho

9710 bronze badges

Collectives™ on Stack Overflow

Adding a single label per group in ggplot with stat_summary and text geoms

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related