R中有光泽:如果不满足某些条件,我怎样才能从renderPlot淡出我的plotOutput？

Question

问题很简单.首先,我在渲染图中尝试了if-else条件.就像是

if (input$Next > 0) {
   plot(...)
}
else {
   return()
}

这没用.即使尚未满足条件,也会显示稍后放置绘图的灰色区域.在下一步中,我尝试使用验证(请参阅 此处).我基本上复制了给定示例中的代码.但是,当实际上不满足条件时,它仍然显示灰色区域.我目前的尝试如下:

ui.R

shinyUI(fluidPage(
   sidebarPanel(
      plotOutput("test"),
      actionButton("Next", "Next")
))

server.R

shinyServer(function(input, output, session) {
function(input, output) {
  output$test <- renderPlot({
     validate(
        need(input$Next > 0)
     )
     pt <- plot(input$Next,2)
     print(pt)
  })
}
})

绘图功能仅用于说明.我看起来不一样.任何帮助都非常感谢!

Answer 1

1. 第一种可能性 -conditionalPanel

我们想要显示plotOutput是否actionButton按下了.更具体地说,如果input.Next > 0.这个条件被评估javaScript,因此我们的语法略有不同 - 而不是$我们.在输入后使用,我们使用括号.

conditionalPanel(
      condition = "input.Next * 1 > 0",
      plotOutput("test")  
    )

  但是,我们乘以input.Next1 是很奇怪的.这是必要的,因为input.Next,期望一个数字,也返回属性.似乎JavaScript不知道如何处理这个......但是乘法可以解决问题.

[1] 0
attr(,"class")
[1] "integer"                "shinyActionButtonValue"

在这个例子中,立即plotOutput出现......肯定太快了.

library(shiny)

ui1 <- shinyUI(fluidPage(
  sidebarPanel(
    conditionalPanel(
      condition = "input.Next * 1 > 0",
      plotOutput("test")  
    ),
    actionButton("Next", "Next")
  )
))


server1 <- shinyServer(function(input, output, session) {

  output$test <- renderPlot({
    pt <- plot(input$Next, 2)
    print(input$Next)
    print(pt)
  })

})

shinyApp(ui1, server1)

2. "减速火车"

在这个例子中,我们将"减速"超速plotOutput.为此,我们需要包装shinyjs.

首先,我们要用一个id 包装conditionalPanel成一个divid,比方说,animation

div(id = "animation",
      conditionalPanel(
        condition = "input.Next * 1 > 0",
        plotOutput("test")  
      )
    )

然后,在服务器端,我们将以下列方式定义动画:条件在输入$ next,div应该显示幻灯片动画.

observe({
        toggle(id = "animation", anim = TRUE, animType = "slide",
              time = 0.5, condition = input$Next > 0)
      })

 

完整示例:

ui2 <- shinyUI(fluidPage(
  # we need to include this function in order to use shinyjs functions
  useShinyjs(), 

  sidebarPanel(
    actionButton("Next", "Next"), 

    div(id = "animation",
        conditionalPanel(
          condition = "input.Next * 1 > 0",
          plotOutput("test"),
          sliderInput("manipulate", "slider", min = 0, max = 1, value = 1)
        )
    )
  )
))


server2 <- shinyServer(function(input, output, session) {

  # Introduce gently the div with an id = "animation" and its all content.
  observe({
    toggle(id = "animation", anim = TRUE, animType = "slide",
           time = 0.5, condition = input$Next > 0)
  })
  # We could animate only the plotOutput with "toogle(id = test")" 
  # - it would work as well, but for the first time the plot is shown
  # way we would get an errors with margins.


  output$test <- renderPlot({
    #plot(input$Next, 2)
    ggplot(iris, aes(x = Species)) + geom_bar(alpha = input$manipulate)

  })
})

shinyApp(ui2, server2)

3. renderUI

正如您所指出的,另一种可能性是使用该功能renderUI.如果要一次渲染多个元素,则必须将它们包装list为如下例所示:

library(shiny)
library(ggplot2)

ui3 <- shinyUI(fluidPage(
  sidebarPanel(
    uiOutput("dynamic"),
    actionButton("Next", "Next")
  )
))


server3 <- shinyServer(function(input, output, session) {

  output$dynamic <- renderUI({
    if (input$Next > 0) {
      # if we want to render more element, we need the list
      list(
        plotOutput("test"),
        sliderInput("manipulate", "slider", min = 0, max = 1, value = 1)
      )
    }
  })


  output$test <- renderPlot({
    #plot(input$Next, 2)
    ggplot(iris, aes(x = Species)) + geom_bar(alpha = input$manipulate)
  })

})

shinyApp(ui3, server3)