r - 使用 Shiny 的动态向网页添加图

Question

我想使用 Shiny 创建一个应用程序，动态地向页面添加绘图。它可能是 10 个地块，也可能只有一个。我正在使用 this tutorial在动态 UI 的 Shiny 主页中。

这是一个简化的例子。
函数showme正在绘制图形

服务器文件

shinyServer(function(input, output) {
  # Create an environment for storing data
  symbol_env <- new.env()
  # Make a chart for a symbol, with the settings from the inputs
  make_chart <- function(symbol) {
    showme(symbol)
  }

  display <- c("1083484" , "1101732")

  output$MyList <- renderUi({ 
    for (i in i:nrow(display))
       renderPlot({make_chart(display[i])})
    })
})

用户界面

shinyUI(pageWithSidebar(
  headerPanel("My Plots !"),
  sidebarPanel(
    wellPanel(
      p(strong("Scan1"))))
 ,mainPanel(
      uiOutput("MyList")
)))

我收到以下错误

Listening on port 8100
Error in .subset2(x, "impl")$defineOutput(name, value, deparse(substitute(value))) : 
  Unexpected character output for display

如果这不是方法 - 我将不胜感激任何指导。
谢谢。

> sessionInfo()
R version 2.15.3 (2013-03-01)
Platform: i386-w64-mingw32/i386 (32-bit)

Answer 1

也许这个由 Winston Chang 提供的例子很有帮助:

Shiny example app with dynamic number of plots

这是一个完整的例子，以防链接腐烂:

server.R

max_plots <- 5

shinyServer(function(input, output) {

# Insert the right number of plot output objects into the web page
output$plots <- renderUI({
  plot_output_list <- lapply(1:input$n, function(i) {
     plotname <- paste("plot", i, sep="")
     plotOutput(plotname, height = 280, width = 250)
   })

   # Convert the list to a tagList - this is necessary for the list of items
   # to display properly.
   do.call(tagList, plot_output_list)
})

# Call renderPlot for each one. Plots are only actually generated when they
# are visible on the web page.
for (i in 1:max_plots) {
    # Need local so that each item gets its own number. Without it, the value
    # of i in the renderPlot() will be the same across all instances, because
    # of when the expression is evaluated.
    local({
        my_i <- i
        plotname <- paste("plot", my_i, sep="")

        output[[plotname]] <- renderPlot({
        plot(1:my_i, 1:my_i, xlim = c(1, max_plots), ylim = c(1, max_plots), main = paste("1:", my_i, ".  n is ", input$n, sep = ""))
        })
    })
}
})

ui.R

shinyUI(pageWithSidebar(

  headerPanel("Dynamic number of plots"),

    sidebarPanel(
      sliderInput("n", "Number of plots", value=1, min=1, max=5)
    ),

    mainPanel(
      uiOutput("plots") # This is the dynamic UI for the plots
    )
))