Selectize inputs not updating correctly in R

Question

I am working with a data set with many more rows, here is a snippet of it in the code. I want the app to show the rows correctly, so BMW PETROL 1 will show: fuel=petrol, mpg =30, colour = red and BMW PETROL 2 will show petrol, 40, blue. etc

But when switching between BMW petrol 1 and 2, it does not update correctly. It seems that "Petrol" existing in both rows is causing the problem.

I thought about doing a if/else statement but I think this would become too complicated since I have many rows with multiple petrol/diesel inputs. I also do not want a button that resets the whole thing, I'd like it to change as the user chooses the vehicle.

(I couldn't find an example with the same problem as this but please send me anything that I may have missed!)

Code:

library(shiny)
Data2 <- data.frame(Vehicle= c("BMW PETROL 1", "BMW PETROL 2", "BMW DIESEL" ), 
                    Fuel_type= c("Petrol", "Petrol", "Diesel"),
                    mpg =c(30, 40, 35), 
                    colour = c("red", "blue", "red"))
ui <- fluidPage(
  useShinyjs(),
  tags$head(
    tags$style(
      HTML("        #div_id .selectize-control.single .selectize-input:after{content: none;}"
           ),
      " #container * {display: inline;}"
      )
    ),
  sidebarPanel( radioButtons("Radiobutton", "Choose the vehicle", Data2$Vehicle, selected = 1),
                tags$div(id= "div_id",
                         selectizeInput("Select1", "Fuel type", choices= NULL),
                         selectizeInput("Select2", "WLTP mpg", choices= NULL),
                         selectizeInput("Select3", "colour", choices= NULL)
                         )
                )
  )

server <- function(input, output, session){

  observeEvent(input$Radiobutton,{
    updateSelectizeInput(session,'Select1',
                         choices = sort(unique(Data2$Fuel_type[Data2$Vehicle == input$Radiobutton])))
    
  })
  observeEvent(input$Select1,{
    updateSelectizeInput(session,'Select2',
                         choices = sort(unique(Data2$mpg[Data2$Vehicle == input$Radiobutton &
                                                           Data2$Fuel_type == input$Select1 ])))
    
  })
  observeEvent(input$Select2,{
    updateSelectizeInput(session,'Select3',
                         choices= sort(unique(Data2$colour[Data2$Vehicle == input$Radiobutton &
                                                          Data2$Fuel_type == input$Select1 &
                                                          Data2$mpg == input$Select2])))
  })
  
  
}
shinyApp(ui = ui, server = server)

user_7972989 · Answer

You're having this problem because when you switch betwen BMW PETROL 1 and BMW PETROL 2, the value of input$Select1 doesn't change. So the observeEvent(input$Select1) does not run.

You can add the event input$Radiobutton to the observeEvent to overcome this.

  observeEvent({input$Select1
               input$Radiobutton},{
    updateSelectizeInput(session,'Select2',
                         choices = sort(unique(Data2$mpg[Data2$Vehicle == input$Radiobutton &
                                                           Data2$Fuel_type == input$Select1 ])))
    
  })

Selectize inputs not updating correctly in R

1 Answers