R Shiny：每次定制都需要一致的随机样本

Question

这是我的第一个问题，如果我不遵守网站的任何规范，请提前致歉！

我正在试验 R Shiny。我正在尝试制作一个应用程序，允许某人自定义许多不同发行版和内核估计器的组件。然而，在我继续之前，我的问题是：每次我在我的应用程序中调整一个滑块或其他可自定义的选项时，都会绘制一个全新的样本。例如，如果我想降低我的内核带宽，我该如何使用一个示例而不更改它？

现在我有以下 ui.R 和 server.R 代码：

    library(shiny)
    shinyUI(bootstrapPage(
      headerPanel("Kernel Estimation"),
      mainPanel(
      sliderInput(inputId = "n_breaks",
          label = "Number of bins in histogram (approximate):",
          min = 1,
          max = 50,
          value = 25),

      sliderInput(inputId = "observations",
         label = "Number of observations:",
         min = 10,
         max = 1000,
         value = 500),

      checkboxInput(inputId = "density",
            label = strong("Show density estimate"),
            value = FALSE),

      # Display this only if the density is shown
      conditionalPanel(condition = "input.density == true",
               sliderInput(inputId = "bw_adjust",
                           label = "Bandwidth adjustment:",
                           min = 0.2, max = 2, value = 1, step = 0.2)),

      conditionalPanel(condition = "input.density == true",
               selectInput(inputId = "kernel",
                           label = "Type of Kernel:",
                           list("Gaussian" = "gaussian", "Epanechnikov" = "epanechnikov", "Rectangular" = "rectangular", "Triangular" = "triangular", "Biweight" = "biweight", "Optcosine" = "optcosine"))),

      checkboxInput(inputId = "individual_obs",
            label = strong("Show individual observations"),
            value = FALSE),

      plotOutput(outputId = "main_plot", height = "300px")

    )))

aaaaa 还有：

    library(shiny)

    shinyServer(function(input, output) {

      output$main_plot <- renderPlot({
        hist(rnorm(input$observations,mean=0,sd=1),
     probability = TRUE,
     breaks = as.numeric(input$n_breaks),
     xlab = "Observations",
     main = "Standard Normal Distribution")

if (input$individual_obs) {
  rug(rnorm(input$observations,mean=0,sd=1), col = "red")
}

if (input$density) {
  dens <- density(rnorm(input$observations,mean=0,sd=1),
                  kernel = input$kernel,
                  adjust = input$bw_adjust)
  lines(dens, col = "blue")
}

      })
    })

产量..哦，废话。我成为会员的时间还不够长，无法 post 图片。我会尝试 post this link，但我不知道这是否会将您带到我的应用程序。

非常感谢您的帮助！

Answer 1

我认为你的问题可以通过像这样在反应函数中生成分布来解决：

get_observations <- reactive(
{
    return(rnorm(input$observations,mean=0,sd=1))
})

if (input$individual_obs) {
  rug(get_observations(), col = "red")
}

if (input$density) {
  dens <- density(get_observations(),
                  kernel = input$kernel,
                  adjust = input$bw_adjust)
  lines(dens, col = "blue")
}

get_observations只会在input$observations改变的时候改变。

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