闪亮的多输出

Question

当我运行Shiny应用程序时，我无法获得“random_comment”，“best”或“最差”数据。有人能指出我正确的方向吗？

我的ui.R文件是

    # This Shiny app will allow users to upvote/downvote my teaching evaluation
# comments on the basis of how "useful" each comment is

library(shiny)

shinyUI(fluidPage(
  headerPanel("Rate my Teaching Evaluations!"),

  mainPanel(
    h4("The current comment:"),
    random_comment,

    tabsetPanel(
      tabPanel("About", 
               "...",
               paste("Currently there are", m, "comments in the dataset.", sep = " ")
               ),
      tabPanel("Most Useful Evaluations", tableOutput("best")),
      tabPanel("Least Useful Evaluations", tableOutput("worst"))     
      )    
    )
  ))

我的server.R文件是

    library(shiny)

shinyServer(
  function(input, output){
    studentsSay <- readLines("studentsSay.txt")
    output$m <- length(studentsSay)

    evalDF <- data.frame(studentsSay, rep(0,m))
    colnames(evalDF) <- c("comments", "rating")

    output$random_comment <- as.character(evalDF[ sample(1:m, 1), "comments"])

    output$best <-  renderTable({head( evalDF[ order(evalDF$rating), "comments" ] )})
    output$worst <- renderTable({tail( evalDF[ order(evalDF$rating), "comments" ] )})

  }
  )

我尝试了一些反应函数，例如renderText和renderTable，但我仍然没有看到输出。

Answer 1

在ui.R文件中，您应该使用：

textOutput({"random_comment"})

和

textOutput({"m"})

在server.R中，您需要renderText功能：

output$m <- renderText(length(studentsSay))

和

renderText(as.character(evalDF[ sample(1:m, 1), "comments"]))

您可以查看Shiny tutorial (Display reactive output)了解详情。