r - 根据 Shiny R 中的单选按钮显示 slider 输入

Question

如何让 slider (例如命名为“Divide mtcars wt”)弹出“选项 b”单选按钮，并将 x 划分为 aes (这是来自 mtcars 数据集的 wt)“选项 b”与下面可重现示例中的 slider 值？然后，如果选择了“选项 a”单选按钮，请再次隐藏该 slider 。我查看了几个堆栈溢出帖子，但它们没有帮助。我不断收到NULL当我实现它时绘制“选项 b”的输出错误，所以我把它拿出来。

library(shiny)
library(ggplot2)
options(warn=-1)

#ui.r
ui <- pageWithSidebar(
  headerPanel("many plots app"),

  sidebarPanel(
    sliderInput("width", "Plot Width (%)", min = 0, max = 100, value = 100), 
    sliderInput("height", "Plot Height (px)", min = 0, max = 800, value = 800),
    uiOutput("filter_plot")

  ),

  mainPanel(
    uiOutput("plot")
  )
)
#server.r
server <- function(input, output, session) {

  options(warn = -1) #This doesn't stop console warning

  output$filter_plot<-renderUI({
    radioButtons("rd","Select Option",choices = c("a",
                                                  "b",
                 selected = "a"))
  })

output$plot <- renderUI({
    if(input$rd=="a"){
      output$plot1<- renderPlot({
        ggplot2::ggplot(mtcars, aes(mpg, cyl))+ geom_point()
      })
      plotOutput("plot1", width = paste0(input$width, "%"), height = input$height)
    }
    else if(input$rd=="b"){
      output$plot2<- renderPlot({
        ggplot2::ggplot(mtcars, aes(wt, qsec))+ geom_line()

      })
      plotOutput("plot2", width = paste0(input$width, "%"), height = input$height)
    }
  })
}
shinyApp(ui = ui, server = server)

先感谢您!

如果可以的话，还有一个好处，即使我隐藏了它们，为什么控制台中还会出现警告。我的应用程序有效，但警告存在:

#Warning: Error in if: argument is of length zero
#  96: renderUI [C:/Users/YOU/Documents/DIRECTORY/xyz.R#443]
#  95: func
#  82: origRenderFunc
#  81: output$plot
#  1: runApp

Answer 1

您可以使用 conditionalPanel显示/隐藏 sliderInput当从您的单选按钮输入中选择“b”时。

为了防止您的警告，您可以要求 req(input$rd)在您的 if 中使用它之前陈述。

让我知道这是否是您想到的行为。

library(shiny)
library(ggplot2)
options(warn=-1)

#ui.r
ui <- pageWithSidebar(
  headerPanel("many plots app"),

  sidebarPanel(
    sliderInput("width", "Plot Width (%)", min = 0, max = 100, value = 100), 
    sliderInput("height", "Plot Height (px)", min = 0, max = 800, value = 800),
    uiOutput("filter_plot"),
    conditionalPanel(
      "input.rd == 'b'",
      sliderInput("sl_wt", "Divide Weight", min = 1, max = 10, value = 5)
    )
  ),

  mainPanel(
    uiOutput("plot")
  )
)
#server.r
server <- function(input, output, session) {

  options(warn = -1) #This doesn't stop console warning to stop

  output$filter_plot<-renderUI({
    radioButtons("rd","Select Option",choices = c("a",
                                                  "b",
                                                  selected = "a"))
  })

  output$plot1<- renderPlot({
    ggplot2::ggplot(mtcars, aes(mpg, cyl))+ geom_point()
  })

  output$plot2<- renderPlot({
    ggplot2::ggplot(mtcars, aes(wt/input$sl_wt, qsec))+ geom_line()
  })

  output$plot <- renderUI({
    req(input$rd)
    if(input$rd=="a"){
      plotOutput("plot1", width = paste0(input$width, "%"), height = input$height)
    }
    else if(input$rd=="b"){
      plotOutput("plot2", width = paste0(input$width, "%"), height = input$height)
    }
  })
}
shinyApp(ui = ui, server = server)