使在一个反应​​性对象内创建的对象对另一个对象可用 [英] Make object created inside one reactive object available to another in shiny

问题描述

我有一个闪亮的应用程序，其中我基于滑块定义对象并从中创建data.frame.这将用于创建绘图，在该绘图下方我想包含一个汇总表.我的问题是必须在反应对象内部定义图以基于滑块进行更新，但是我发现当我尝试访问对象以在不同反应对象内部打印摘要时，找不到.

I have a shiny app in which I define an object based on sliders and create a data.frame from it. This gets used to create a plot, below which I'd like to include a summary table. My issue is that the plot must be defined inside of a reactive object to update based on the sliders, but I found that when I tried to access the object to print a summary inside of a different reactive object, it wasn't found.

我不想让相同的计算代码运行两次，只是为了使该对象进入另一个反应对象.我的两个初步想法:

I'd like to not run through the same calculation code twice just to get the object into the other reactive object. My two initial ideas:

• 我尝试在第一个反应对象中使用save(object, file = "...")，然后在第二个反应对象中使用load(file = "...")，但是它没有更新.
• 我曾想过在反应式plotOutput定义之外定义对象，但是我敢肯定，当用户输入更改时，它不会更新.它只会保留初始input对象默认设置的值.

• I tried using save(object, file = "...") inside the first reactive object and then putting load(file = "...") inside the second, but it doesn't update.
• I thought of defining my object outside of my reactive plotOutput definition, but I'm pretty sure it won't update when user inputs are changed; it will just stay with the value of the initial input object default settings.

好吧，只是继续尝试了后一个想法，它甚至还没有走得那么远:

Well, just went ahead and tried the latter idea, and it doesn't even get that far:

• 我将其放在shinyServer(...)之前，并且它无法生成数据，因为我的通话取决于input，并且此时不知道input.
• 我把它放在shinyServer(...)之后但在renderPlot(...)之前，试图为所有输出对象创建某种全局可用"的对象，这让我为尝试做一些在反应式之外使用input的事情而感到责备功能.

• I put it before shinyServer(...) and it can't generate the data because my call depends on input and it doesn't know about input at that point.
• I put it after shinyServer(...) but before renderPlot(...) to try and make sort of a "globally available" object for all output objects, and it scolding me for trying to do something that uses input outside of a reactive function.

下面是一个示例，该示例是从Shiny的"Hello Shiny！"修改而来的.例子:

Here's an example to illustrate, modified from Shiny's "Hello Shiny!" example:

ui.R

library(shiny)

# Define UI for application that plots random distributions 
shinyUI(pageWithSidebar(

  # Application title
  headerPanel("Hello Shiny!"),

  # Sidebar with a slider input for number of observations
  sidebarPanel(
    sliderInput("obs", 
                "Number of observations:", 
                min = 1,
                max = 1000, 
                value = 500)
  ),

  # Show a plot of the generated distribution
  mainPanel(
    plotOutput("distPlot"),
    tableOutput("summary")
  )
))

server.R

library(shiny)

# Define server logic required to generate and plot a random distribution
shinyServer(function(input, output) {

  output$distPlot <- renderPlot({

    # generate an rnorm distribution and plot it
    dist <- rnorm(input$obs)
    hist(dist)
  })

  output$summary <- renderTable({
    #dist <- rnorm(input$obs)
    summary <- table(data.frame(cut(dist, 10)))
  })
})

如果按原样运行它，则cut将抛出错误，因为它不了解dist.如果您取消注释我们在plotOutput中重新定义dist的行，则它将起作用.

If you run it as is, cut will throw and error because it doesn't know about dist. If you uncomment the line where we re-define dist as is done in plotOutput, then it will work.

这是简单的代码-我的代码涉及更多，我真的不希望只运行两次以使另一个反应式输出知道相同的结果.

This is simple code -- mine is quite a bit more involved and I'd really prefer not to run it twice just to make the same result known to another reactive output.

建议?

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