Set the maximum number of choices made by pickerInput()

Question

Im trying to limit the max number of choices made by pickerInput() to two in shiny app but I cannot make it work.

library(shiny)
library(shinydashboard)
library(plotly)
library(shinyWidgets)
header <- dashboardHeader()

sidebar <- dashboardSidebar(
  
  
  fluidRow(column(12,
                  pickerInput(
                    inputId = "iss",
                    label = "Issue", 
                    choices = colnames(mtcars),
                    multiple = T,
                    options =  list("max-options-group" = 2)
                  )           
  ))
  
)

body <- dashboardBody(fluidPage(
  
  
  )
  
)


ui <- dashboardPage(title = 'Search', header, sidebar, body)


server <- function(input, output, session) {
  
  
  
}
shinyApp(ui = ui, server = server)

Answer 1

The problem is that you are using "max-options-group" but you are not using any groups in your choices. You must use "max-options" = 2 in the options argument of pickerInput().

For completeness, this is the modified version of your code. We cannot pick more than 2 options with it:

library(shiny)
library(shinydashboard)
library(plotly)
library(shinyWidgets)
header <- dashboardHeader()

sidebar <- dashboardSidebar(
  
  
  fluidRow(column(12,
                  pickerInput(
                    inputId = "iss",
                    label = "Issue", 
                    choices = colnames(mtcars),
                    multiple = T,
                    options =  list("max-options" = 2)
                  )           
  ))
  
)

body <- dashboardBody(fluidPage(
  
  
)

)


ui <- dashboardPage(title = 'Search', header, sidebar, body)


server <- function(input, output, session) {
  
  
  
}
shinyApp(ui = ui, server = server)