Define programmatically a tooltip in ggplot and tidyverse

Question

I would like to print an interactive ggplot graph using plotly. I use the plotly "tooltip" argument. I would like to use a variable argument to define the text argument of the aesthetic in ggplot.

This is the code :

library(tidyverse)
library(plotly)

df <- data.frame(ID = paste0("ID_",LETTERS[1:20]),
                 A = rnorm(20),
                 B = rnorm(20),
                 C = rnorm(20),
                 D = rnorm(20),
                 E = rnorm(20)
                 )

variable_to_tooltip <- c("C", "D")

graph <- df %>% 
  ggplot(aes(x=A, y = B,
             text = paste("ID", ID,
                          "<br>C", C,
                          "<br>D", D)))+
  geom_point()

ggplotly(graph, tooltip = "text")

The graph is OK, but I would like to use the "variable_to_tooltip" to define the text argument as the graph will be include in a loop and it will vary.

I did try to use the get() and !!sym() functions but didn't really understand how sym() was working nor if it could be useful to solve this problem.

Thanks a lot if someone can help ! Florent

Answer 1

One option would be to use tidyr::unite to create your tooltip and to add it as a column to your dataframe outside of ggplot:

library(tidyverse)
library(plotly)

set.seed(123)

df <- data.frame(
  ID = paste0("ID_", LETTERS[1:20]),
  A = rnorm(20),
  B = rnorm(20),
  C = rnorm(20),
  D = rnorm(20),
  E = rnorm(20)
)

variable_to_tooltip <- c("C", "D")

df <- df |> 
  unite(col = tooltip, all_of(c("ID", variable_to_tooltip)), sep = "<br>")

graph <- df %>%
  ggplot(aes(
    x = A, y = B,
    text = tooltip
  )) +
  geom_point()

ggplotly(graph, tooltip = "text")