Use case_when with geom_text to automatically label points that mmeet certain conditions (extrema, significance, etc.) #rstatstips

tips-highlight-features.r

library(tidyverse)
library(ggrepel)      # substitude geom_text for geom_text_repel if you don't want to bother with this!

mydata =
  data_frame(
    x = 1:10,
    y = rnorm(10),
    name = c('Apple', 'Banana', 'Kiwi', 'Orange', 'Watermelon',
      'Grapes', 'Pear', 'Cantelope', 'Tomato', 'Satsauma')) %>%
  mutate(
    name_interesting  = case_when(
      y < 0 ~ name,     # keep the labels for points you want to highlight
      # you can add more criteria here!
      TRUE ~ ""))       # ditch the rest

ggplot(mydata, aes(x = x, y = y)) +
  # note: both geoms inherit x and y aesthetics
  geom_point(size = 5) +
  geom_text_repel(aes(label = name_interesting), point.padding = 2)

Whoops! There was also also one missing on line 9 😅