Question

我有一个闪亮的应用程序，基本上遵循以下设置：

library(shiny)

weights <- data.frame("weights" = c(1, 2))

# Define UI for application that draws a histogram
ui <- fluidPage(

   # Application title
   titlePanel("Old Faithful Geyser Data"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
         sliderInput("variable1",
                     "Weight 1",
                     min = 1,
                     max = 50,
                     value = weights[1,])
      ),

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

# Define server logic required to draw a histogram
server <- function(input, output) {

   output$distPlot <- renderPlot({
      # generate bins based on input$bins from ui.R
      x    <- faithful[, 1]*input$variable1

      bins <- seq(min(x), max(x), length.out = input$bins + 1)

      # draw the histogram with the specified number of bins
      hist(x, breaks = bins, col = 'darkgray', border = 'white')
   })
}

# Run the application 
shinyApp(ui = ui, server = server)

但我有+100个不同的变量，所以实际上复制这段代码的每一行100次（像这样）似乎很麻烦：

x    <- faithful[, 1]*input$variable1
y    <- faithful[, 1]*input$variable2
z    <- faithful[, 1]*input$variable3

xx <- x+y+z # I would plot xx

我是否缺少更优雅的解决方案？也许有反应功能？

Answer 1

如评论所述，我建议如：

rowSums(sapply(1:100, function(var) faithful[, 1]*input[[paste0("variable", var)]]))

您可以在下面找到可重复的示例（带有2个输入）：

library(shiny)
weights <- data.frame("weights" = c(1, 2))
ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      sliderInput("variable1", "Weight 1",min = 1, max = 50, value = weights[1,]),
      sliderInput("variable2", "Weight 2",min = 1, max = 50, value = weights[2,])
    ),
    mainPanel(
      plotOutput("distPlot")
    )
  )
)

server <- function(input, output) {
  output$distPlot <- renderPlot({
    data <- rowSums(sapply(1:2, function(var) faithful[, 1]*input[[paste0("variable", var)]]))
    hist(data, col = 'darkgray', border = 'white')
  })
}

shinyApp(ui = ui, server = server)

在Shiny中更改默认输入变量的优雅方法

1 个答案: