r - Change hover over values in a plotly plot

I have the following Shiny Application:

library(shiny)
library(plotly)

ui <- fluidPage(

  plotlyOutput("plot")
)

server <- function(input, output) {

  # renderPlotly() also understands ggplot2 objects!
  output$plot <- renderPlotly({
    plot_ly(mtcars, x = ~mpg, y = ~wt)
  })


}

shinyApp(ui, server)

If I now hoover over a point I get values like: (14.5, 17.3). Is there an easy way to make sure these values appear as:

mpg: 12.3 [enter]
wt: 45.2

Answer

I believe the following does what you want:

library(shiny)
library(plotly)

ui <- fluidPage(
  plotlyOutput("plot")
)

server <- function(input, output) {


  # renderPlotly() also understands ggplot2 objects!
  output$plot <- renderPlotly({
    plot_ly(mtcars, 
            x = ~mpg, 
            y = ~wt,  
            hoverinfo="text", 
            text = ~paste0("mpg: ", mpg, "\nwt: ", wt))
  })


}

shinyApp(ui, server)

Hope this helps!