Shiny 中反应式条件 renderImage 的困难-解网

问：

我试图在以下 Shiny 应用程序中有条件地显示图像。

有 2 个问题。

首先，虽然如果我取消注释，我可以显示图片，但我无法以其他方式显示图像（尽管与图像关联的 Alt 文本确实显示）。#img(src = "dollar.png")

第二个问题是，我试图根据的值使语句被动地工作，但没有成功。ifne

因为我有：ui.R

library(shiny)

shinyUI(fluidPage(

  #  Application title
  titlePanel("My App that Won't Show Pics!"),

  sidebarLayout(
    sidebarPanel(
      # Simple integer interval
      sliderInput("ns", "Hypothetical NS with Treatment:", 
                  min=100, max=10000, value=4000),

      sliderInput("RPS", "RPS:", 
                  min = 0, max = 50000, value = 21594, step = 100),
      # Revenue Delta
      sliderInput("revDelta", "RPS Delta:", 
                  min = -10000, max = 5000, value = -4900, step = 100),
      # NS Lift
      sliderInput("nsLift", "NS Lift (See PPT for example results):", 
                  min = 0, max = .4, value = .18, step = .001)

    ),

    # Show a table summarizing the values entered
    mainPanel(
      tableOutput("values"),
      imageOutput("image1")
      #img(src = "dollar.png")

    )
  )
))

因为我有：server.R

library(shiny)
net_effect <- function(ns, revDelta, nsLift, RPS) {
  trBase     <- (ns/(1 + nsLift)) * RPS
  trOffer    <- (ns * RPS) + (ns * revDelta)
  netEffect  <- round(trOffer - trBase)
  return(paste("$",format(netEffect, big.mark=","),sep=""))
}

shinyServer(function(input, output) {

  sliderValues <- reactive({

    # Compose data frame
    data.frame(
      Name = c("New Students with Offer", 
               "Rev per Student", "Net Effect"),
      Value = as.character(c(input$ns, 
                             input$RPS,
                             ne <- net_effect(input$ns, input$revDelta, input$nsLift, input$RPS))), 
      stringsAsFactors=FALSE)
  }) 

  # Show the values using an HTML table
  output$values <- renderTable({
    sliderValues()
  })
  # image2 sends pre-rendered images
  output$image1 <- renderImage({

    if (net_effect(input$ns, input$revDelta, input$nsLift, input$RPS) < 0) {
      return(list(
        src = "images/red_dollar.png",
        contentType = "image/png",
        alt = "We're losing money!"
      ))
    } else if (net_effect(input$ns, input$revDelta, input$nsLift, input$RPS) > 0) {
      return(list(
        src = "images/dollar.png",
        filetype = "image/png",
        alt = "We're making money!"
      ))
    }

  }, deleteFile = FALSE)
})

r 闪亮

net_effect <- function(ns, revDelta, nsLift, RPS) {
  trBase     <- (ns/(1 + nsLift)) * RPS
  trOffer    <- (ns * RPS) + (ns * revDelta)
  return(round(trOffer - trBase)) # new return value 
}

shinyServer(function(input, output) {

  net <- reactive({ 
    net_effect(input$ns, input$revDelta, input$nsLift, input$RPS)
  })


  sliderValues <- reactive({

    # Compose data frame
    data.frame(
      Name = c("New Students with Offer", 
               "Rev per Student", "Net Effect"),
      Value = as.character(c(input$ns, 
                             input$RPS,
                             ne <- paste("$",format( net(), big.mark=","),sep="") )), 
      stringsAsFactors=FALSE)
  }) 


  # Show the values using an HTML table
  output$values <- renderTable({
    sliderValues()
  })

  output$image1 <- renderImage({

    if ( net() < 0) { 
      return(list(
        src = "www/red_dollar.png",
        contentType = "image/png",
        alt = "We're losing money!"
      ))
    } else if (net() > 0) {
      return(list(
        src = "www/dollar.png",
        filetype = "image/png",
        alt = "We're making money!"
      ))
    }

  }, deleteFile = FALSE)
})

Shiny 中反应式条件 renderImage 的困难

Difficulty with reactive conditional renderImage in Shiny

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