Question

我正在尝试使用R Shiny创建一个APP。我想上传数据（.csv文件）。然后我想在下拉菜单中填充CSV文件中的列名。我无法做到这一点。

请参阅以下代码：

---- server.r -----

library(shiny)
options(shiny.maxRequestSize = 32*1024^2)


shinyServer(


function(input, output){ 

data <- reactive({
  file1 <- input$file
  if(is.null(file1)){return()} 
  read.table(file=file1$datapath,head=TRUE,sep=",")

})

output$sum <- renderTable({
  if(is.null(data())){return ()}
  summary(data())

})

output$table <- renderTable({
  if(is.null(data())){return ()}
  data()
})

# the following renderUI is used to dynamically generate the tabsets when the file is loaded. Until the file is loaded, app will not show the tabset.
output$tb <- renderUI({
  if(is.null(data()))
    h5("no file loaded")
  else
    tabsetPanel(tabPanel("Data", tableOutput("table")),tabPanel("Summary", tableOutput("sum")))
})

   output$col <- renderUI({

  selectInput("phenomena", "Select the Phenomena",  names(data))
  })

})

----- ui.R -----

 library(shiny)


 shinyUI(fluidPage(

 titlePanel("Hotspot Analysis of EnviroCar Data"),
 sidebarLayout(
 sidebarPanel(

  # uploading the file 
   fileInput("file","Upload *.csv file"), # fileinput() function is used to get the file upload contorl option

  uiOutput("col")


),

mainPanel(  uiOutput("tb") )

)

))

Answer 1

我想问题出在server.R：

selectInput("phenomena", "Select the Phenomena",  names(data))

在这里，您使用data而没有括号，因此您实际获得的是函数data的源代码，而names(data)是NULL。我认为您只需要names(data)替换names(data())。

无法在R闪亮中动态填充下拉菜单

1 个答案: