Expand/Collapse Shiny selectInput function

Question

I would like to find a resource that would allow my Shiny selectInput function to expand/collapse based on the category headings that I have created. I have searched through some bootstrap resources, but am not yet successful. Please forgive my minimal working example, I acknowledge that there may be more efficient ways to provide a MWE. Thanks for any advice you can offer.

library(shiny)
library(tidyverse)
#create a quick dataset to plot
schools <-  as.data.frame(table(
    c('Adams', 'Van Buren', 'Clinton', 'Douglas', 'Edwards', 
              'Franklin', 'Grant', 'Harrison', 'Ignatius', 'Justice', 
              'Kellogg', 'Lincoln'), 
    dnn = list("school")))

enrollment <- as.data.frame(table(
    c(300, 305, 265, 400, 500, 450, 475, 900, 800, 850, 1200, 1500), 
    dnn = list("enrollment")))

schoolsDataframe <- schools %>% 
    bind_cols(enrollment) %>% 
    select(school, enrollment)

#define data elements for selectInput choices argument
elem <- c('Adams', 'Van Buren', 'Clinton', 'Douglas')
mid <- c('Edwards', 'Franklin', 'Grant')
high <- c('Harrison', 'Ignatius', 'Justice')
multi <- c('Kellogg', 'Lincoln')

# Define UI 
ui <- fluidPage(
    tags$style(".optgroup-header { color: #FFFFFF !important; background: #000000 !important; }"),
    # Application title
    titlePanel("Expandable selectInput"),

    # Sidebar with a select input
    sidebarLayout(
        sidebarPanel(
            selectInput(inputId = 'schoolsInput',
                        label = 'Select a school',
                        choices = list('Elementary' = elem, 
                                       'Middle' = mid, 
                                       'High' = high, 
                                       'Multi-level' = multi), 
                        selectize = TRUE)
        ),

        # Show a plot 
        mainPanel(
           plotOutput("myPlot")
        )
    )
)

# Define server logic required to draw a plot
server <- function(input, output) {

    output$myPlot <- renderPlot({
        #filter the data based on selectInput
schoolsDataframe <- schoolsDataframe %>% 
    filter(school == input$schoolsInput)
        # draw the plot
ggplot(data = schoolsDataframe, 
       mapping = aes(x = school, 
                     y = enrollment))+
    geom_col()
    })
}

# Run the application 
shinyApp(ui = ui, server = server)

Answer 1

Here's a start for you, although it may not be exactly what you want. I think you want a dynamic selection list, based on the school type (elementary, middle...). Here's a way you can do that with 2 selection lists, where the lower one is dynamic, responding to the choice in the upper selection list.

I also tried to simplify your data setup. You can copy/paste the code to run it.

library(shiny)
library(tidyverse)

#define data elements 
schools <- data.frame (schoolName=  c('Adams', 'Van Buren', 'Clinton', 'Douglas', 'Edwards','Franklin', 'Grant', 'Harrison', 'Ignatius', 'Justice', 'Kellogg', 'Lincoln'),
                      schoolType = c('Elementary','Elementary','Elementary','Elementary','Middle','Middle','Middle','High','High','High','Multi-level','Multi-level'),
                      schoolEnrollment = c(300, 305, 265, 400, 500, 450, 475, 900, 800, 850, 1200, 1500))

# Define UI 
ui <- fluidPage(
  tags$style(".optgroup-header { color: #FFFFFF !important; background: #000000 !important; }"),
  # Application title
  titlePanel("Expandable selectInput"),

  # Sidebar with a select input
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = 'schoolType',
                  label = 'Select a School Type',
                  choices = list('Elementary',
                                 'Middle', 
                                 'High', 
                                 'Multi-level'), 
                  ),
      selectInput("schoolName", "Select School:","Elementary"),
    ),

    # Show a plot 
    mainPanel(
      plotOutput("myPlot")
    )
  )
)

# Define server logic required to draw a plot
server <- function(input, output, session) {

  # Set up the selection for counties
  observe ({
    selectionSchoolNames <- sort(unique(unlist(subset(schools$schoolName,schools$schoolType==input$schoolType))))
    updateSelectInput(session, "schoolName", choices = selectionSchoolNames)
  })

  output$myPlot <- renderPlot({
    #filter the data based on selectInput
    schoolsDataframe <- schools %>% 
      filter(schoolType == input$schoolType)
    # draw the plot
    ggplot(data = schoolsDataframe, 
           mapping = aes(x = schoolName, 
                         y = schoolEnrollment))+
      geom_col()
  })
}

# Run the application 
shinyApp(ui = ui, server = server)