Vary the choices in selectinput based on other conditions in shiny R

Question

I have a selectInput panel in shiny. I only dealt with the fixed values of choices in selectInput till now.

Now I am at a point where I want to vary these choices based on some other conditions in shiny Ui.

Example:

Ui.R

shinyUI(fluidPage(
fluidRow(column(3,
wellPanel(
                  h4("Data Upload"),
                  fileInput('file1', h5('Choose Your Model Data'), accept=c('text/csv','text/comma-separated-values,text/plain','.OUT')),
                  fileInput('file2', h5('Choose Your Observation Data'), accept=c('text/csv','text/comma-separated-values,text/plain','.xlsx'))    
                ),  
wellPanel(uiOutput("check"))))

Server.R

shinyServer(function(input, output) {
output$check <- renderUI({
   selectInput("check", label = h4("Dataset Selection"), choices = c("Model" = 1, "Observation" = 2, "Both" = 3), selected = 1, multiple = F )
  })
a <- reactive({
   fileinput1 <- input$file1
   if (is.null(fileinput1))
   return(NULL)
   read.table(fileinput1$datapath, header = TRUE, col.names = c("Ei","Mi","hours","Nphy","Cphy","CHLphy","Nhet","Chet","Ndet","Cdet","DON","DOC","DIN","DIC","AT","dCCHO","TEPC","Ncocco","Ccocco","CHLcocco","PICcocco","par","Temp","Sal","co2atm","u10","dicfl","co2ppm","co2mol","pH"))
 })

 #Upload Observation Data 

 b <- reactive({
   fileinput2 <- input$file2
   if (is.null(fileinput2))
   return(NULL)
   #xlfile <- list.files(pattern = ".xlsx")
   xlfile <- fileinput2[1]
   wb <- loadWorkbook(xl_file)
   sheet_ct <- wb$getNumberOfSheets()
   b <- rbindlist(pblapply(1:sheet_ct, function(x) {
     res <- read.xlsx(xl_file, x)
   }), fill=TRUE)
   b <- b [-c(1),]
   print (b)
   })

Now I want to make the choices in selectInput dynamic based on the file input.

See the ?updateSelectInput and its family functions to handle these problems. Also take a look at ?conditionalPanel. — nicola
I have tried updateselectinput and failed to update the choices list in realtime....Its like if the user uploads file1 I need to update the choice list based on that as just "Model"...If he then uploads the second file then provide all three options..if just 2nd file is uploaded then choices = just "Observation". Please let me know how this can be achieved. — cppiscute

Neville Andrade Neville Andrade · Accepted Answer · 2014-10-28T13:54:26

I have tried to correct some of the issues in the server.R file. Note that I followed the following algorithm

if file1 is uploaded first then choice is "Model"
if file2 is uploaded subsequently then choices should be "Model", "Observation", "Both"
if file2 is uploaded first the choice is "Observation"
if file1 is uploaded subsequently then choices should be "Model", "Observation", "Both"

library(shiny) library(xlsx)

shinyServer(function(input, output) {

  a <- reactive({
    fileinput1 <- input$file1
    if (is.null(fileinput1))
      return(NULL)
    #read.table(fileinput1$datapath, header = TRUE, col.names = c("Ei","Mi","hours","Nphy","Cphy","CHLphy","Nhet","Chet","Ndet","Cdet","DON","DOC","DIN","DIC","AT","dCCHO","TEPC","Ncocco","Ccocco","CHLcocco","PICcocco","par","Temp","Sal","co2atm","u10","dicfl","co2ppm","co2mol","pH"))

    #Please change this part back to your code as I dont have your file based on the column names above
    read.table(fileinput1$datapath, header= TRUE)
  })

  #Upload Observation Data 

  b <- reactive({
    fileinput2 <- input$file2
    if (is.null(fileinput2))
      return(NULL)
    #xlfile <- list.files(pattern = ".xlsx")
    xlfile <- fileinput2$datapath
    wb <- loadWorkbook(xlfile)
    sheet_ct <- wb$getNumberOfSheets()
    b <- rbind(list(lapply(1:sheet_ct, function(x) {
      res <- read.xlsx(xlfile, x)
    })))
    b <- b [-c(1),]
    print(b)
  })

  getModel <- reactive({
    if(!is.null(a()) & !is.null(b()))
    {
      c("Model", "Observation", "Both")
    }
    else if(!is.null(a()))
    {
      "Model"
    }
    else if(!is.null(b()))
    {
      "Observation"
    }


  })
  output$check <- renderUI({
    selectInput("check", label = h4("Dataset Selection"), choices = as.list(getModel()), multiple = F )
  })


})

Vary the choices in selectinput based on other conditions in shiny R

1 Answers