CODEWITHSUNDEEP
rggplot2
Anurag N. Sharma
Anurag N. Sharma

Reputation: 372

How to add text to ggplot below the graph?

I'm looking at figures from Moreira et al. (Nature, 2020) where they have graphs indicating sample size and treatments under the barplots such as this:

Moreira et al.

Is there a way to reproduce this in ggplot? This would be very useful to indicate all the necessary information regarding an experiment in a compact manner.

Some dummy data for the plot:

library(tidyverse)

tibble(
  Rodent = c(rep("Mouse",11),
             rep("Hamster",7),
             rep("Guinea pig",4),
             rep("Gerbil",12)),
  `Weight (gm)` = rnorm(34,25,10),
  `Long whiskers` = c(rep("+",11),rep("-",7),rep("+",4),rep("-",12)),
  `Long tail` = c(rep("+",11),rep("-",7),rep("+",4),rep("-",12)),
  `Albino or normal` = c(rep("Albino",11),rep("Normal",7),rep("Albino",4),rep("Normal",12))
) %>% 
  ggplot(aes(Rodent,`Weight (gm)`,fill = `Albino or normal`)) +
  geom_boxplot()

Upvotes: 2

Views: 409

Answers (1)

stefan
stefan

Reputation: 124138

There are probably two or three approaches to achieve your desired result. Personally I prefer to do it via patchwork, i.e create a second plot with the additional information you want to display and glue it to your main plot:

library(tidyverse)

d <- tibble(
  Rodent = c(rep("Mouse",11),
             rep("Hamster",7),
             rep("Guinea pig",4),
             rep("Gerbil",12)),
  `Weight (gm)` = rnorm(34,25,10),
  `Long whiskers` = c(rep("+",11),rep("-",7),rep("+",4),rep("-",12)),
  `Long tail` = c(rep("+",11),rep("-",7),rep("+",4),rep("-",12)),
)

p1 <- d %>% 
  ggplot(aes(Rodent,`Weight (gm)`)) +
  geom_boxplot()

d1 <- d %>% 
  select(-`Weight (gm)`) %>%
  count(Rodent, `Long whiskers`, `Long tail`) %>% 
  distinct() %>% 
  mutate(n = as.character(n)) %>% 
  pivot_longer(-Rodent)

p2 <- d1 %>% 
  ggplot(aes(Rodent, fct_rev(name), label = value)) +
  geom_text(size = 10) +
  labs(x = NULL, y = NULL) +
  theme_minimal() +
  theme(panel.grid = element_blank(), axis.text.x = element_blank())

library(patchwork)

p1 / p2

EDIT With a legend on the right it looks like so. I simply added a color legend where I mapped Rodent on color:

p1 <- d %>% 
  ggplot(aes(Rodent,`Weight (gm)`, color = Rodent)) +
  geom_boxplot() +
  theme(legend.position = "right")

p2 <- d1 %>% 
  ggplot(aes(Rodent, fct_rev(name), label = value)) +
  geom_text(size = 10) +
  labs(x = NULL, y = NULL) +
  theme_minimal() +
  theme(panel.grid = element_blank(), axis.text.x = element_blank())

p1 / p2

Upvotes: 3

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