'闭合'类型的对象不是子集：R闪亮的应用程序

Question

I am trying to create graph app using R shiny. So I take input from the user for route, stop/trip id, (boarding, alighting or load) from the user. So the ui.r is

ui <- fluidPage(
  pageWithSidebar(
    headerPanel('FAST_TRIPS Visulization', windowTitle = "Fast_trips Visaualization"),
    sidebarPanel(
      selectInput('route', 'Choose the Route No.', unique(y['route_id'])),
      selectInput('id', 'Please Choose Stop or Trip ID', c('stop_id','trip_id')),
      selectInput('rider', 'What do you wanna compare?', c('boarding', 'alighting', 'load')),
      radioButtons('method','Please select your method', c('Sum', 'Average'))),
    mainPanel(

      plotOutput('plot1')

    )
  )
)

Then I am trying to extract the data for the specific route and aggregate values for example boarding with stop_id and trying to create a barplot for those stop_id. The server.R is below

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

  # Combine the selected variables into a new data frame



  selectedData <- reactive({
    y[c('route_id', input$id, input$rider)]

  })

  data <- reactive({
    subset(selectedData, route_id == input$route)
    })
  a <- reactive({
    aggregate(input$rider~input$id,data,input$method)
    })

  s <- reactive({input$rider})

output$plot1 <- renderPlot({barplot(a[s])})

}

But I am getting the following error:

Error: object of type 'closure' is not subsettable

Please help me with this . I am new to shiny.

Answer 1

You should access to reactive expression as a function, so you need to add () to any call to a variable created as a reactive expression.

Instead of:

subset(selectedData, route_id == input$route)

try using:

subset(selectedData(), route_id == input$route)

or even use a extra variable to avoid problems.

selectedData_ <- selectedData()
subset(selectedData_, route_id == input$route)

Finally, you don't need to put a single input into a reactive expression, just used it into any other reactive expression as renderPlot .

Insted of

s <- reactive({input$rider})
output$plot1 <- renderPlot({barplot(a[s])})

Use only

output$plot1 <- renderPlot({
  a_ <- a()
  barplot(a_[input$rider])
})

Please note that since you didn't provide any representative data for y , I was unable to test your code completely, but this answer should resolve the closure error.