select input depending on previous select input shiny-CodePudding

I have a database and I need to make that in the first selecInput shows the name of 4 diferents columns and according whit the selection, in the next selecIpunt show the categories that correpond to the column selected. I have something like this in my server:

output$SelectCategory <-renderUI({
   selectInput("SelectCategory", "Select Category",
               choices = c("A"="colname1",
                           "B"="colname2",
                           "C"="colname3",
                           "D"="colname4")) 
 }) 
 
 output$SelectProc <-renderUI({
   selectInput("SelectProc", "Select Procedure",
               choices=input$SelectCategory, multiple = T, selected = TRUE)

CodePudding user response：

Something like this shows you how you can update the choices for the second selectInput:

library(shiny)
df = data.frame(
  colname1=c("apple","banana", "pear"),
  colname2=c("water", "juice", "milk")
)

ui <- fluidPage(
  selectInput("SelectCategory", "Select Category",
              choices = c("fruits"="colname1",
                          "drinks"="colname2")),
  uiOutput("SelectProc")
)

server <- function(input, output, session) {
  output$SelectProc <- renderUI(
    selectInput("SelectProc", "Select Procedure", 
                choices=df[[input$SelectCategory]])
  )
}

shinyApp(ui, server)

CodePudding user response：

I added UI parts and with a minor change of choices= c(), it is working but user need to select items when they appear in the dropdown Select Procedure.

   ui <- fluidPage(
  uiOutput('SelectCategory'),
  uiOutput('SelectProc')
)

server <- function(input,output,session){
  output$SelectCategory <-renderUI({
    selectInput("SelectCategory", "Select Category",
                choices = c("A"="colname1",
                            "B"="colname2",
                            "C"="colname3",
                            "D"="colname4")) 
  }) 
  
  output$SelectProc <-renderUI({
    selectInput("SelectProc", "Select Procedure",
                choices=c(input$SelectCategory), multiple = T,selected = T) 
  }) 
#end of server 
}
  
  shinyApp(ui = ui, server = server)

However, if you wish to update upon selection in Category, more change in server needed (See comments)

  server <- function(input,output,session){
  output$SelectCategory <-renderUI({
    selectInput("SelectCategory", "Select Category",
                choices = c("A"="colname1",
                            "B"="colname2",
                            "C"="colname3",
                            "D"="colname4")) 
  }) 
  
  output$SelectProc <-renderUI({
    selectInput("SelectProc", "Select Procedure",
                choices=NULL, #c(input$SelectCategory), #choices be made NULL
                multiple = F,selected = T)   #Multiple be made FALSE
  })
  # added an observer with updateSelectInput
  observe(
    {input$SelectCategory
    updateSelectInput(session = session,
                      inputId = 'SelectProc',label = "Select Procedure",
                      choices = c(input$SelectCategory)
                      )
    
  })
  
  # end of server
  }