Question

selectInput(
  inputId = "histvariable", 
  label = "Select a variable",
  choices = list("Age", "SibSp", "Parch", "Fare")
)

我想问一下我是否可以使choices更具“动态性”？我的意思是choices可以从.csv文件中选择所有变量。上面的示例代码仅从.csv文件中选择四个变量（Age，SibSp，Parch，Fare）。

Answer 1

这是一个SelectInput的代码段，基于上载的csv文件的名称。

library(shiny)
  ui = fluidPage(
    tabsetPanel(
      tabPanel("“Dynamic” Choice on SelectInput in Shiny
  ",
               sidebarLayout(
                 sidebarPanel(
                   fileInput('file1', 'Upload your  CSV File'),
                   htmlOutput("varselectOne")),
                 mainPanel(
                    verbatimTextOutput("rendertext")
                 )))))


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

    myData1 <- reactive({
      inFile <- input$file1
      if (is.null(inFile)) return(NULL)
      data <- read.csv(inFile$datapath, header = TRUE, sep=",")
      data
    })

    #observe(print(myData1()))

    output$varselectOne <- renderUI({
      #browser()
      req(myData1())
      # Variable selection:
      selectInput(inputId = "varsOne", label = "Variables to use:", choices=names(myData1()), selected=names(myData1()), multiple =FALSE)
    })

     output$rendertext <- renderPrint ({
      req(input$varsOne) #To ensure values are available before proceeding with a calculation or action, 
                         #and prevent ?renderPrint from through an error before file uploaded
      input$varsOne
    })

  }

  shinyApp(ui = ui, server = server)

Shiny中SelectInput的“动态”选择

1 个答案: